tag:blogger.com,1999:blog-59853781178306000982024-03-15T18:10:20.635-07:00your electrical homehamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.comBlogger1086125tag:blogger.com,1999:blog-5985378117830600098.post-11263958013107986852024-01-23T03:27:00.000-08:002024-01-23T03:29:25.886-08:00Work Environment<p> </p><span><a name='more'></a></span><p><br /></p><p dir="ltr" style="text-align: left;"></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> The work environment can be described as anywhere you work.
The condition of the work environment plays an important role in making the
workplace safer. A safe work environment goes a long way toward preventing
accidents, injuries, and illnesses. There are many ways to describe a safe work
environment, but generally it would contain a well-organized shop layout, use of
shop policies and procedures, safe equipment, safety equipment, safety
training, employees who work safely, good supervision, and a workplace culture
that supports safe work practices. Conversely, a shop that is cluttered with
junk, poorly lit, and full of safety hazards is unsafe (FIGURE 3-9).</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1RLm-EerWuvx8hbzlZeo_lFbUFlWofSh8uksELJFq36nCGjAdDzAlICcz1oa5JgxlD5KL32SOxJsqjw7roAV9ou8N-qig5puLXUDr5QhvwvKqbq-9Be2BjZD-Uzc71UsZdcV1-V-QjDVXHACJTADNsxjthbYnpqA4f05VjM4uNiC1qE0yvUusmGNeDpz8/s801/3-9.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="801" data-original-width="585" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1RLm-EerWuvx8hbzlZeo_lFbUFlWofSh8uksELJFq36nCGjAdDzAlICcz1oa5JgxlD5KL32SOxJsqjw7roAV9ou8N-qig5puLXUDr5QhvwvKqbq-9Be2BjZD-Uzc71UsZdcV1-V-QjDVXHACJTADNsxjthbYnpqA4f05VjM4uNiC1qE0yvUusmGNeDpz8/s16000/3-9.jpg" /></a></div><br /><p class="MsoNormal" dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: left;"></p><p dir="ltr" style="text-align: left;"></p><p class="MsoNormal" dir="ltr" style="text-align: left;"><b style="text-align: right;"><u><span style="color: #00b0f0;">OSHA and EPA</span></u></b></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"><span style="text-align: right;"> OSHA stands for the Occupational Safety and Health Administration (OSHA). It is a U.S. government agency that was created to provide national leadership in occupational safety and health, and it works toward finding the most effective ways to help prevent worker fatalities and workplace injuries and illnesses. OSHA has the authority to conduct workplace inspections and, if required, fine employers and workplaces if they violate its regulations and procedures (FIGURE 3-10). For example, a fine may be imposed on the employer or workplace if a worker is electrocuted by a piece of faulty machinery that has not been regularly tested and maintained.</span></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1PZeOxlodqwQuJ4SLJP3k8PSUvaIkjo_FEckZ72PGbAfQ-Brgkm6meWVy694NzyLGTVRs5vbI0QP5za-YROxELGqFPvWTL7cP_wxI439RC_a7aG_6RgkRp3ADcv0kW1c4m9gKIpaJiOREMuDDnK-sr9rfRoc-l2VN_QnVxrA4JhQYDHXpczRy-Y9HFgWw/s543/3-10.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="412" data-original-width="543" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1PZeOxlodqwQuJ4SLJP3k8PSUvaIkjo_FEckZ72PGbAfQ-Brgkm6meWVy694NzyLGTVRs5vbI0QP5za-YROxELGqFPvWTL7cP_wxI439RC_a7aG_6RgkRp3ADcv0kW1c4m9gKIpaJiOREMuDDnK-sr9rfRoc-l2VN_QnVxrA4JhQYDHXpczRy-Y9HFgWw/s16000/3-10.jpg" /></a></div><br /><span style="text-align: right;"><br /></span><p></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> EPA stands for the Environmental Protection Agency. This
federal government agency deals with issues related to environmental safety.
The EPA conducts research and monitoring, sets standards, conducts workplace
inspections, and holds employees and companies legally accountable in order to
keep the environment protected. Shop activities need to comply with EPA laws
and regulations by ensuring that waste products are disposed of in an
environmentally responsible way, chemicals and fluids are correctly stored, and
work practices do not contribute to damaging the environment (FIGURE 3-11).</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4lakkaqgQ7SyRzZhoiK4HXZ-4zKXyj9lX1iIt-zLKks8CmCdE3jAB6mzg8-iknKo70sKrIo7DmalerFmhfr1o2dVAXJG86vl10IZkl94tOm_qSaS-Qu2J9Eyx4iTLs2d91HOD_80_aqaUA-LhlqHuUp2_vPLoWwAlhOOmOdZ2Seu-KI_oFNIXQZtOkL69/s560/3-11.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="414" data-original-width="560" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4lakkaqgQ7SyRzZhoiK4HXZ-4zKXyj9lX1iIt-zLKks8CmCdE3jAB6mzg8-iknKo70sKrIo7DmalerFmhfr1o2dVAXJG86vl10IZkl94tOm_qSaS-Qu2J9Eyx4iTLs2d91HOD_80_aqaUA-LhlqHuUp2_vPLoWwAlhOOmOdZ2Seu-KI_oFNIXQZtOkL69/s16000/3-11.jpg" /></a></div><br /><p class="MsoNormal" dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr"></p><p class="MsoNormal" style="text-align: justify;"></p><p></p><p class="MsoNormal"></p><p></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"><b><u><span style="color: red;">Applied Science</span></u></b></p><p dir="ltr" style="text-align: left;"></p><p class="MsoNormal" style="text-align: justify;"><b>AS-2</b>:<b>Environmental lssues: The technician develops and maintains
an understanding of all federal, state, and local rules and regulations
regarding environmental issues related to the work of the automobile
technician. </b></p><p class="MsoNormal" style="text-align: justify;"> You need to keep up to date with local laws and regulations
regarding environmental issues.There are large lines associated with
disregarded environmental regulations. To remain informed. you can log on to
local state websites to check the latest laws and regulations.The US
Environmental Protection Agency (EPA) website also has up-to-date information
on environmental regulations (www.epa.gov/lawsregs/). More information can be
found on the specific regulations for the automotive industry at <a href="http://www.epagovilawsregslsectorslautomotive/">www.epagovilawsregslsectorslautomotive</a>.
html.This site has a full listing of laws and regulations. Compliance measures.
and enforcement tactics. For additional laws that are FIGURE 3-11 Correct
chemical storage. enforced by your local state environmental agencies. go to
wwwepa.gov/epahome/state.htm.</p><p class="MsoNormal" dir="ltr" style="text-align: justify;">
</p><p class="MsoNormal" dir="ltr" style="text-align: justify;"><b>AS-3: Environmental issues: The technician uses such things
as government impact statements, media information, and general knowledge of
pollution and waste management to correctly use and dispose of products that
result from the performance of a repair task. </b></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> When you complete a job. you must
be able to identify what to do with any waste products created from the repair
task This could be as simple as knowing where and how to recycle cardboard
boxes or as complex as knowing what to do with brake components that may
contain asbestos. Normally there is a table posted in the garage that details
the correct measures for disposing of and storing waste material. A sample
table follows:</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvtb8RRDxYWLWDd7XEZrVzFiQ25bwqtpiQ5c-9e2QqAxzD4iqaa7GxZRjZL2JHZrx755lx5LNLZLKliXqSKd6JZEZZwvtdhOrwoTQRVwXBZASa6fQq5iQDqzshfxGMkcu8lB27LclkraED_WoHaUrjmLypbxlzn36E41-rXW42jHqSQfKJJQT-wfjf5Qyr/s1172/content.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1172" data-original-width="1083" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvtb8RRDxYWLWDd7XEZrVzFiQ25bwqtpiQ5c-9e2QqAxzD4iqaa7GxZRjZL2JHZrx755lx5LNLZLKliXqSKd6JZEZZwvtdhOrwoTQRVwXBZASa6fQq5iQDqzshfxGMkcu8lB27LclkraED_WoHaUrjmLypbxlzn36E41-rXW42jHqSQfKJJQT-wfjf5Qyr/w591-h640/content.png" width="591" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><p class="MsoNormal" dir="ltr" style="text-align: left;"><b><u><span style="color: #00b0f0;">Shop Policies and
Procedures<o:p></o:p></span></u></b></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> Shop policies and procedures are a set of documents that
out-line how tasks and activities in the shop are to be conducted and managed. They also ensure that the shop
operates according to OSHA and EPA laws and regulations. A policy is a guiding
principle that sets the shop direction, and a procedure is a list of the steps
required to get the same result each time a task or activity is performed
(FIGURE 3-12). An example of a policy is an OSHA document for the shop that
describes how the shop complies with legislation, such as a sign simply saying,
“Safety glasses must be worn at all times in the shop.” An example of a
procedure is a document that describes the steps required to safely use the
vehicle hoist. </p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghaN73trbc6GOGwpHlW-Jewivwh5_0-xCFu75R0Mv3f0XdbrsTdoxgT10MRsANk5dt6tEKJKzfxni_uCRzw_t1IsivhfVovpYHfymYKkhGeTZ8al3z55azt7nkpTYTYyBf61Pdw_spP38UJO2McnLFlhGTxtVfCbPc4xPhDcfapnWHockj4rVjEtdKce3_/s1007/3-12.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1007" data-original-width="582" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghaN73trbc6GOGwpHlW-Jewivwh5_0-xCFu75R0Mv3f0XdbrsTdoxgT10MRsANk5dt6tEKJKzfxni_uCRzw_t1IsivhfVovpYHfymYKkhGeTZ8al3z55azt7nkpTYTYyBf61Pdw_spP38UJO2McnLFlhGTxtVfCbPc4xPhDcfapnWHockj4rVjEtdKce3_/s16000/3-12.jpg" /></a></div><br /><p class="MsoNormal" dir="ltr" style="text-align: justify;"><br /></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> Each shop has its own set of policies and procedures and a
system in place to make sure the policies and procedures are regularly reviewed
and updated. Regular reviews ensure that new policies and procedures are
developed and old ones are modified in case something has changed. For example,
if the shop moves to a new building, then a review of policies and procedures
will ensure that they relate to the new shop, its layout, and equipment. In
general, the policies and procedures are written to guide shop practice; help
ensure compliance with laws, statutes, and regulations; and reduce the risk of
injury. Always follow your shop policies and procedures to reduce the risk of
injury to your coworkers and yourself and to prevent damage to property.</p><p class="MsoNormal" dir="ltr" style="text-align: justify;">
</p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> It is everyone’s responsibility to know and follow the
rules. Locate the general shop rules and procedures for your workplace. Look
through the contents or index pages to familiarize yourself with the contents.
Discuss the policy and the shop rules and procedures with your supervisor. Ask
questions to ensure that you understand how the rules and procedures should be
applied and your role in making sure they are followed.</p><p dir="ltr" style="text-align: left;"></p><div style="text-align: justify;"><br /></div><p></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com1tag:blogger.com,1999:blog-5985378117830600098.post-43296097400581852842023-12-06T14:13:00.000-08:002023-12-06T14:24:37.139-08:00Safety Overview<p dir="ltr" style="text-align: left;"> </p><div dir="ltr" style="text-align: left;"><span><a name='more'></a></span></div><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"></p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> Motor vehicle servicing is one of the most common vocations
worldwide. Hundreds of thousands of shops service millions of vehicles every
day. That means at any given time, many people are conducting automotive
servicing, and there is great potential for things to go wrong (FIGURE 3-3}.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi67VJmaZiWp03fO38EDE-LtWKCPFdjIC4ApZfVTfFrvkVmzzlYfGfwWf5pZoIGKnHXH9WPZbQ5vauzpUDWNeyGv3Shf1jJiHKsLymeO3BzT_4VBP14bS0s-IHbsuw1B845K7bB7qaOqLYrIZCnmkIiDkL5KhhFSGm3TRD9YvYlKhnFpofQcWn0v0mcK2t9/s441/33.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="345" data-original-width="441" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi67VJmaZiWp03fO38EDE-LtWKCPFdjIC4ApZfVTfFrvkVmzzlYfGfwWf5pZoIGKnHXH9WPZbQ5vauzpUDWNeyGv3Shf1jJiHKsLymeO3BzT_4VBP14bS0s-IHbsuw1B845K7bB7qaOqLYrIZCnmkIiDkL5KhhFSGm3TRD9YvYlKhnFpofQcWn0v0mcK2t9/s16000/33.PNG" /></a></div><br /><p class="MsoNormal" dir="ltr" style="text-align: justify;"><br /></p><div dir="ltr" style="text-align: justify;"><p class="MsoNormal"> It is up to you and your workplace to make sure all work
activities are conducted safely. Accidents are not caused by properly
maintained tools; accidents are generally caused by people.</p><p style="text-align: left;"></p><p class="MsoNormal"></p><p></p><p class="MsoNormal" style="text-align: left;"></p><p></p></div><p dir="ltr" style="text-align: left;"></p><p class="MsoNormal" dir="ltr" style="text-align: left;"><span style="color: #2f9c6f; text-align: justify;"><b><u>TECHNICIAN TIP</u></b></span></p><div dir="ltr" style="text-align: justify;"><div style="text-align: justify;"></div><p class="MsoNormal"> Whenever you perform a task in the shop, you must use
personal protective clothing and equipment that are appropriate for the task
and that conform to your local safety regulations and policies.Among other
items, these may include:</p>
<p class="MsoNormal"><span style="color: #38761d;">■</span>Work clothing. such as coveralls and steel-capped footwear</p>
<p class="MsoNormal"><span style="color: #38761d;">■</span>Eye protection, such as safety glasses and face masks</p>
<p class="MsoNormal"><span style="color: #38761d;">■</span>Ear protection, such as earmuffs and earplugs</p>
<p class="MsoNormal"><span style="color: #38761d;">■</span>Hand protection. such as gloves and barrier cream</p>
<p class="MsoNormal"><span style="color: #38761d;">■</span>Respiratory equipment, such as face masks and valved
respirators</p>
<p class="MsoNormal"><span style="color: #38761d;">■</span>If you are not certain what is appropriate or required.
Ask your supervisor".</p><p class="MsoNormal"><b><u><span style="color: #2f9c6f;">You Are the Automotive Technician </span></u></b></p>
<p class="MsoNormal"> You are changing the oil on a new type of vehicle for the
first time.The oil pan has the drain plug on the side of the oil pan instead of
the bottom of the pan.You place the drain pan directly under the drain plug
like you normally do. Unfortunately, when the plug comes out, the oil shoots
sideways right over the side of the drain pan.You reposition it quickly, but
not before a large puddle is on the floor.</p>
<p class="MsoNormal">1. Why is it important to review the SDS before cleaning up
a spill?</p>
<p class="MsoNormal">2. What is the minimum PPE that should be worn to manage
this spill?</p>
<p class="MsoNormal">3.<span style="mso-spacerun: yes;"> </span>What are some of
the health hazards of coming into frequent or prolonged contact with used
engine oil?</p>
<p class="MsoNormal">4. If the oil were to catch fire, what fire extinguisher
should be used to put the fire out?</p><p class="MsoNormal"><b><u><span style="color: #2f9c6f;">Don't Underestimate the Dangers<o:p></o:p></span></u></b></p></div><p class="MsoNormal" dir="ltr" style="text-align: left;">
</p><p class="MsoNormal" dir="ltr" style="text-align: justify;"> Because vehicle servicing and repair are so commonplace, it
is easy to overlook the many potential risks related to this field. Think
carefully about what you are doing and how you are doing it. Think through the
steps, trying to anticipate things that may go wrong and taking steps to
prevent them. Also be wary of taking shortcuts. In most cases, the time saved
by taking a shortcut is nothing compared to the time spent recovering from an
accident (FIGURE 3-4).</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyrWF4JOeEfIU49XShyphenhyphen8aXr1gixPcBVShkRT84pyVLS3sHRYS2yBa93vCDR7L5Uj-cN7J75sOv01HFdZE-zrhsfJAew7p1RQUSSykWNc9YN8op7LXSyHuBxJEnLVB7GYZLFzNkCuYb9e6RJ5Ux7VS1Kj0Sam3P12yc-BwPlc35X767pwe0L-Gyxh2PwhM3/s573/34.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="381" data-original-width="573" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyrWF4JOeEfIU49XShyphenhyphen8aXr1gixPcBVShkRT84pyVLS3sHRYS2yBa93vCDR7L5Uj-cN7J75sOv01HFdZE-zrhsfJAew7p1RQUSSykWNc9YN8op7LXSyHuBxJEnLVB7GYZLFzNkCuYb9e6RJ5Ux7VS1Kj0Sam3P12yc-BwPlc35X767pwe0L-Gyxh2PwhM3/s16000/34.PNG" /></a></div><br /><p class="MsoNormal" dir="ltr" style="text-align: justify;"><br /></p><div dir="ltr" style="text-align: justify;"><p class="MsoNormal"><b><u><span style="color: #2f9c6f;">Accidents and Injuries Can Happen at Any Time<o:p></o:p></span></u></b></p>
<p class="MsoNormal"> There is the possibility of an accident occurring whenever
work is undertaken. For example, fires and explosions are a constant hazard
wherever there are flammable fuels. Electricity can kill quickly as well as
cause painful shocks and burns. Heavy equipment and machinery can easily cause
broken bones or crush fingers and toes. Hazardous solvents and other chemicals
can burn or blind as well as contribute to many kinds of illness. Oil spills
and tools left lying around can cause slips, trips, and falls. Poor lifting and
handling techniques can cause chronic strain injuries, particularly to your
back (FIGURE 3-5).</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-GqMGdQl3yuUTQk2xXu_elQJNBwM-hYdkkswKWXKLq5DrxDBrNxJVABA0iVcYRHPToPMNHmNEWAZ1W0YHXCH3JRjh0b9q3dHFrU1UounpRJJa09myoImzI_BDIeihVPPrUhQzwJe4hqJZ_hrbUNvupTokMgvdXVoSbh_VNTGKVld1eshQg94zLnYZnRll/s367/35.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="290" data-original-width="367" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-GqMGdQl3yuUTQk2xXu_elQJNBwM-hYdkkswKWXKLq5DrxDBrNxJVABA0iVcYRHPToPMNHmNEWAZ1W0YHXCH3JRjh0b9q3dHFrU1UounpRJJa09myoImzI_BDIeihVPPrUhQzwJe4hqJZ_hrbUNvupTokMgvdXVoSbh_VNTGKVld1eshQg94zLnYZnRll/s16000/35.PNG" /></a></div><br /><p class="MsoNormal"><br /></p><p class="MsoNormal"><b><u><span style="color: #2f9c6f;">Accidents and Injuries Are Avoidable<o:p></o:p></span></u></b></p>
<p class="MsoNormal"> Almost all accidents are avoidable or preventable by taking
a few precautions. Think of nearly every accident you have witnessed or heard
about. In most cases someone made a mistake. Whether caused by horseplay,
neglecting maintenance on tools or equipment, or using tools improperly, these
instances lead to injury (FIGURE 3-6).</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYqoanO4NES-BHOMvXkOlRD413eICw7yLPd8hnU0U6OSgi8J6Sr3fgMs2RHDOo7kYajriAQXai2vA8tM117saxrZoES6DUq0ZgGfKl6R4_DjI7U7CZv-uReHABdpWQPIt34PXxtTzCy59KFtA34tnmhfrqXS_YpA0hJf7TFGzi2_LCRDr0_BIjzGMluP3M/s619/36.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="370" data-original-width="619" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYqoanO4NES-BHOMvXkOlRD413eICw7yLPd8hnU0U6OSgi8J6Sr3fgMs2RHDOo7kYajriAQXai2vA8tM117saxrZoES6DUq0ZgGfKl6R4_DjI7U7CZv-uReHABdpWQPIt34PXxtTzCy59KFtA34tnmhfrqXS_YpA0hJf7TFGzi2_LCRDr0_BIjzGMluP3M/s16000/36.PNG" /></a></div><br /><p class="MsoNormal"><br /></p>
<p class="MsoNormal"> Most of these accidents can be prevented if people follow
policies and develop a “safety first” attitude. By following regulations and
safety procedures, you can make your workplace much safer. Learn and follow all
of the correct safety procedures for your workplace. Always wear the right PPE,
and stay alert and aware of what is happening around you. Think about what you
are doing, how you are doing it, and its effect on others. You also need to
know what to do in case of an emergency. Document and report all accidents and
injuries whenever they happen, and take the proper steps to make sure they
never happen again. </p><p class="MsoNormal"><b><u><span style="color: #2f9c6f;">Evacuation Routes<o:p></o:p></span></u></b></p>
<p class="MsoNormal"> Evacuation routes are a safe way of escaping danger and
gathering in a prearranged safe place where everyone can be accounted for in
the event of an emergency. It is important to have more than one evacuation
route in case any single route is blocked during the emergency. Your shop may
have an evacuation procedure that clearly identifies the evacuation routes
(FIGURE 3-7).</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghjzDZFy6cMEIHET1r_04uffPymfFOG-lLa4OxYzuGYQl_wm6m_TMepCrlJuOSGV28IaUZ1C_8L3CkNrrKpQ5X30VsVQQ_6U47jAIBnv09mTAIMokVoQFO_3TplOx0wFbXlqzxylisd2KoKip73Ey2WhZwUuGbKp1YRPcMk3d0T0lqyVydY5pkp4R8ElIl/s385/38.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="296" data-original-width="385" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghjzDZFy6cMEIHET1r_04uffPymfFOG-lLa4OxYzuGYQl_wm6m_TMepCrlJuOSGV28IaUZ1C_8L3CkNrrKpQ5X30VsVQQ_6U47jAIBnv09mTAIMokVoQFO_3TplOx0wFbXlqzxylisd2KoKip73Ey2WhZwUuGbKp1YRPcMk3d0T0lqyVydY5pkp4R8ElIl/s16000/38.PNG" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><br /><p class="MsoNormal"><br /></p>
<p class="MsoNormal"> Often the evacuation routes are marked with colored lines
painted or taped on the floors. Exits should be highlighted with signs that may
be illuminated, and should never be chained closed or obstructed (FIGURE 3-8].</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6b06EwAswYnITNNEGBvNMb6d2jP09WqAkVhm6dDCRopdoYHA1DWM1-oK6jqqmcD6_ysEyPUAgs7c3gzO_32jtns0Z9OBViClFR0jQmmuAyQK2am0cPYsbMrcowXvCnldAjQYEFBjw_fXK-0HF2G4joQ-jUjPd9S9JWMXBgwS478rSJ4KfC4aVMdy7YZ_I/s359/37.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="359" data-original-width="310" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6b06EwAswYnITNNEGBvNMb6d2jP09WqAkVhm6dDCRopdoYHA1DWM1-oK6jqqmcD6_ysEyPUAgs7c3gzO_32jtns0Z9OBViClFR0jQmmuAyQK2am0cPYsbMrcowXvCnldAjQYEFBjw_fXK-0HF2G4joQ-jUjPd9S9JWMXBgwS478rSJ4KfC4aVMdy7YZ_I/s16000/37.PNG" /></a></div><br /><p class="MsoNormal"><br /></p>
<p class="MsoNormal"> Always make sure you are familiar with the evacuation routes
for the shop. Before conducting any task, identify which route you will take if
an emergency occurs.</p><p class="MsoNormal"><b><u><span style="color: #2f9c6f;">TECHNICIAN TIP<o:p></o:p></span></u></b></p><p class="MsoNormal">
</p><p class="MsoNormal"> Never place anything in the way of evacuation routes.
including equipment, Tools, Parts, cleaning supplies, or vehicles.</p><br /></div>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-20825684761981874112023-12-06T13:49:00.000-08:002023-12-06T14:14:14.435-08:00Introduction to automotive Safety<p dir="ltr" style="text-align: left;"> </p><span><a name='more'></a></span><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"></p><p class="MsoNormal" style="text-align: justify;"> Occupational safety and health is very important to ensure
that everyone can work without being injured. Governments normally have
legislation in place, with significant penalties for those who do not follow
safe practices in the workplace. Potential hazards are in most workplaces,
especially automotive shops. It is important to learn about hazards so you can
identify them and take action to protect yourself and your coworkers (FIGURE
3-I ). </p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjb1iI23sBU03QWq25mDS33jEflfL7vrdveCCq0NTsvGGqBM9oeq4OTVmFfK4CjFCWVWEyygh9YXLLRbTr-KZaeU5y70BlekEjYw2BnPKzUjPpUeApVPld8UDNERFmvOtFqjgbMN1nLgMeKTxmMeEu5upO1IvjMfdCj1Pn2hcel2p5K_NrUpeuQyx_l4U88/s459/31.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="459" data-original-width="367" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjb1iI23sBU03QWq25mDS33jEflfL7vrdveCCq0NTsvGGqBM9oeq4OTVmFfK4CjFCWVWEyygh9YXLLRbTr-KZaeU5y70BlekEjYw2BnPKzUjPpUeApVPld8UDNERFmvOtFqjgbMN1nLgMeKTxmMeEu5upO1IvjMfdCj1Pn2hcel2p5K_NrUpeuQyx_l4U88/s16000/31.PNG" /></a></div><br /><p class="MsoNormal" style="text-align: justify;"><br /></p>
<p class="MsoNormal" style="text-align: justify;"> Some hazards are obvious, such as vehicles falling from
hoists or jacks, or tires exploding during inflation. Other hazards are less
obvious, such as the long-term effects of breathing fumes from solvents. There
are many things to learn about safety in the automotive shop, but it is
impossible to cover every situation you will encounter. One of the most
important skills to learn is the ability to recognize unsafe practices or
equipment and put in place measures to prevent injuries from happening.</p>
<p class="MsoNormal" style="text-align: left;"></p><p class="MsoNormal" style="text-align: justify; text-justify: inter-ideograph;"> Occupational
safety and health is everyone’s responsibility. You have a responsibility to
ensure that you work safely and take care not to put others at risk by acting
in an unsafe manner. Your employer also has a responsibility to provide a safe
working environment. To ensure the safety of yourself and others, make sure you
are aware of the correct safety procedures at your work- place. This means
listening very carefully to safety information provided by your employer and
asking for clarification, help, or instructions if you are unsure how to perform
a task safely. Always think about how you are performing shop tasks, be on the
lookout for unsafe equipment and work practices, and wear the correct personal
protective equipment (PPE). PPE refers to items of safety equipment like safety
footwear, gloves, clothing, protective eyewear, and hearing protection (FIGURE
3-2).</p><br /><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha24SDYqJ4O8dHwtJ2hhwCdJruinXxvVqMpv3sUBvpKdSTbCpCZAEiscHsoF4q6N0Wv3ZyZtaDfLmvehyYK5ohqNFgzUdrMVbiYznHiyFvrvcp-7O1je03kAxxaJSoF8Hmj9mQujZsM0vjTXlmjISlUtjbJNpTRDtQ3zdojmLVqeeZGTOXNcVmzkdWALM-/s433/32.PNG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="367" data-original-width="433" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha24SDYqJ4O8dHwtJ2hhwCdJruinXxvVqMpv3sUBvpKdSTbCpCZAEiscHsoF4q6N0Wv3ZyZtaDfLmvehyYK5ohqNFgzUdrMVbiYznHiyFvrvcp-7O1je03kAxxaJSoF8Hmj9mQujZsM0vjTXlmjISlUtjbJNpTRDtQ3zdojmLVqeeZGTOXNcVmzkdWALM-/s16000/32.PNG" /></a></div><br /><p class="MsoNormal" style="text-align: left;"><br /></p><p></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-62325130655675517592023-10-30T03:28:00.002-07:002023-10-30T03:28:10.202-07:00 Gas Laws<p dir="ltr" style="text-align: left;"><span style="text-align: left;"><span></span></span></p><a name='more'></a><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: left;"><span style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u><b>(a) Boyle's Law</b></u></span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> English scientist Robert Boyle investigated the relationship between the volume of a dry ideal gas and its pressure. It states that at constant temperature, the pressure is inversely proportional to the volume of a definite amount of gas. Mathematically,</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbLXU3l9AmAkHGG4G7D2KdLW8BroLzpAEoZTFfrq8yj3gMCdPxmKDxHuCV-t4IHxpvn3vVdDG29NXs43rhLCpeSlRjsn4SAJlYIWU3YtRIQ5SCW8xCbuWilu7hyK46UAGopUuLNyC63vg-gzslzR7eNoGfHEKzv9-GO1RtxppI85011rOnI1Yx0TUXdY_S/s686/1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="342" data-original-width="686" height="199" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbLXU3l9AmAkHGG4G7D2KdLW8BroLzpAEoZTFfrq8yj3gMCdPxmKDxHuCV-t4IHxpvn3vVdDG29NXs43rhLCpeSlRjsn4SAJlYIWU3YtRIQ5SCW8xCbuWilu7hyK46UAGopUuLNyC63vg-gzslzR7eNoGfHEKzv9-GO1RtxppI85011rOnI1Yx0TUXdY_S/w400-h199/1.png" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><b><u>(b) Charle's Law</u></b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> French scientist Jacques Charles experimented with gas under constant pressure and his observations have been formalized into Charle's law.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The volume of a gas at constant pressure is directly proportional to the absolute temperature. Mathematically, it can be expressed as: </span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEio7fgjZGJ_ROuuB3LQYVOZIb1HGItBuw72v0csaXl_whyphenhyphenNbaX2tocjYyxUAoiyIOJbuYr6EnOcreLlMiZ8Z7HXhtFKvGb4PXv5pQxtUJPBB_b9vwHqFaDkVXKgbhFRqhSHxhmPlaGdjgl9K5Rh9J2x1Zun64qrnArgZTc6Hv3g_HgDtbkf9PStt_pi_hN-/s743/2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="363" data-original-width="743" height="195" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEio7fgjZGJ_ROuuB3LQYVOZIb1HGItBuw72v0csaXl_whyphenhyphenNbaX2tocjYyxUAoiyIOJbuYr6EnOcreLlMiZ8Z7HXhtFKvGb4PXv5pQxtUJPBB_b9vwHqFaDkVXKgbhFRqhSHxhmPlaGdjgl9K5Rh9J2x1Zun64qrnArgZTc6Hv3g_HgDtbkf9PStt_pi_hN-/w400-h195/2.png" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><b><u>(c) Gay-Lussac's Law</u></b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> French scientist Joseph Gay-Lussac investigated the relationship between the pressure of a gas and its temperature. It states that the pressure of a gas at constant volume is directly proportional to the absolute temperature. The mathematical statement is as follows:</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLJpji0BoPEW3eVa64xJsQcQTdxdeoFV6_d1wdcBKtgLGZfB9Fl3-gP8nC7fx61gIaoHQx9CJquUGONAdwiCikXQosCZ_19wPutTgL1m-EylMMF19BC6cEVqRfM_z3Ke-bDTCdNUg31A5yLqTqiuU0LOBEZkV6OAqVZ-pHHCsP9qnlbyK-ZFcM8e9jg9zW/s745/3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="365" data-original-width="745" height="196" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLJpji0BoPEW3eVa64xJsQcQTdxdeoFV6_d1wdcBKtgLGZfB9Fl3-gP8nC7fx61gIaoHQx9CJquUGONAdwiCikXQosCZ_19wPutTgL1m-EylMMF19BC6cEVqRfM_z3Ke-bDTCdNUg31A5yLqTqiuU0LOBEZkV6OAqVZ-pHHCsP9qnlbyK-ZFcM8e9jg9zW/w400-h196/3.png" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><b><u>(d) Combined Gas Laws</u></b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Any two of the three gas laws of Boyle, Charles, or Gay-Lussac can be combined, hence the name, combined gas law. In short, this combined gas law is used when it is difficult to keep either the temperature or pressure constant:</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh48vbvJw-2emzHagm7Uaiy774_gCBSTZTc7ws02HEnhMvp_UIeRtLD_6Qr7L6yCzuJHVnbjaaGqdPlcV0IxvXV5-WSvuDL_IGm04uG-Oo9oGmrUOzcgEeziMr0eJ1BoG5YVSW63KNc3FUMRgaKuEzzvWzWM99HrmJo_q9ARMEtvHgH5MO0ZrWBH7Dn17EC/s345/4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="79" data-original-width="345" height="73" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh48vbvJw-2emzHagm7Uaiy774_gCBSTZTc7ws02HEnhMvp_UIeRtLD_6Qr7L6yCzuJHVnbjaaGqdPlcV0IxvXV5-WSvuDL_IGm04uG-Oo9oGmrUOzcgEeziMr0eJ1BoG5YVSW63KNc3FUMRgaKuEzzvWzWM99HrmJo_q9ARMEtvHgH5MO0ZrWBH7Dn17EC/s320/4.png" width="320" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> This relationship can be used to predict pressure, volume, and temperature relationships where any five of the six variables are known.</span></p><p dir="ltr" style="text-align: left;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-1258692281178729532023-10-29T11:31:00.000-07:002023-10-29T11:31:06.747-07:00Venturi Effect<p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> </span></p><div dir="ltr" style="text-align: left;"><span><span style="font-size: medium;"><a name='more'></a></span></span></div><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A fluid passing through smoothly varying constrictions is subject to changes in velocity and pressure, as described by Bernoulli's principle. In case of fluid or airflow through a tube or pipe with a constriction in it, the fluid must speed up in the restriction, reducing its pressure, and producing a partial vacuum.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> As shown in the <span style="color: #800180;">Fig.1</span> fluid density = (ρ), area = (A), and velocity = (V). Let the properties of fluid at entrance and exit be ( ρ<sub style="text-align: right;">1</sub>, A<sub style="text-align: right;">1</sub>, V<sub style="text-align: right;">1</sub>) and at constriction be (ρ<sub style="text-align: right;">2</sub>, A<sub style="text-align: right;">2</sub>, V<sub style="text-align: right;">2</sub>). There is a drop in pressure at the constriction as shown by the height of the column and it is due to conservation of energy. The fluid experiences a gain in kinetic energy and a drop in pressure as it enters the constriction; this effect is called Venturi effect, it is named after the Italian physicist Giovanni Battista Venturi.</span></p><p dir="ltr" style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHmhfhOOZluHYZIZ56Ih_Ot_kz2TjwRUqEy3Yovnu9D6_WFS_tBedwmniyY8dIbbNDJqfQoL_PQY3qam4ehfcOX_5OQPA3dDvZMlx-gZp1574i9mOsAyII9jlk7Gn6eY1vx0DSbtdIv2FduVhiRRu273PkwUAkBnf_288wmBOz6yrhJGYtF9phoHmV_egk/s1015/1.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="597" data-original-width="1015" height="235" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHmhfhOOZluHYZIZ56Ih_Ot_kz2TjwRUqEy3Yovnu9D6_WFS_tBedwmniyY8dIbbNDJqfQoL_PQY3qam4ehfcOX_5OQPA3dDvZMlx-gZp1574i9mOsAyII9jlk7Gn6eY1vx0DSbtdIv2FduVhiRRu273PkwUAkBnf_288wmBOz6yrhJGYtF9phoHmV_egk/w400-h235/1.png" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u>Continuity Equation</u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> It is simply a mathematical expression of the principle of conservation of mass. Mass is neither created nor destroyed. For a steady flow, it states that:</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUq4TzJv0fWFxw9roymBHcL8HOiBOKjJ6x3enj8RvjQsmEFRH9N56QZcTiI7i37Oi8cXV99DV83PYv54wzIprHzO48X_5iImGacBT4MsC-YIkYbmppceM8i7JJfhbfQ_QQ9UkZ3fR-lWcWxMkEPvYPJ1EcrfOI5kL-Ry_Ncaj4Sq_u403MMaaa6JLPqoRM/s625/2.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="162" data-original-width="625" height="83" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUq4TzJv0fWFxw9roymBHcL8HOiBOKjJ6x3enj8RvjQsmEFRH9N56QZcTiI7i37Oi8cXV99DV83PYv54wzIprHzO48X_5iImGacBT4MsC-YIkYbmppceM8i7JJfhbfQ_QQ9UkZ3fR-lWcWxMkEPvYPJ1EcrfOI5kL-Ry_Ncaj4Sq_u403MMaaa6JLPqoRM/s320/2.png" width="320" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy3SbmuAR4BdQOdF7G_TdcM4blOLO__fwyO9gY4cBBuKvmceK5YUADV456nItlCEKLvxCVYT0L082NWwk9xBHJnfrRXtmaBcsSFiRyfzO8esMw6KNlqPRwPAYwxMZcro6BREA9uXrPjxhnJpO9AmVICLlMZ_APqch3mHLXP6vz2zpo-C6LFSsNJUFn9JYQ/s929/3.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="270" data-original-width="929" height="93" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy3SbmuAR4BdQOdF7G_TdcM4blOLO__fwyO9gY4cBBuKvmceK5YUADV456nItlCEKLvxCVYT0L082NWwk9xBHJnfrRXtmaBcsSFiRyfzO8esMw6KNlqPRwPAYwxMZcro6BREA9uXrPjxhnJpO9AmVICLlMZ_APqch3mHLXP6vz2zpo-C6LFSsNJUFn9JYQ/s320/3.png" width="320" /></a></div><br /><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The "continuity equation” is a direct consequence of the rather trivial fact that what goes into the pipe must come out. This has the important consequence that as the area of the hole decreases, the velocity of the fluid must increase, in order to keep the flow rate </span><span style="font-size: large;">constant.</span></p><p dir="ltr" style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u><b>Specific Weight, Density, and Specific Gravity</b></u></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> (a) Specific Weight or Weight Density</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> The weight per unit volume of a substance. Usually it is expressed in N/m</span><sup style="text-align: right;">3</sup><span> or lbs/ft</span><sup style="text-align: right;">3</sup><span>. Mathematically,</span></span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6UO_1pN7ev9mq27uXUE4J_3ByM5UovJM6Q45ht90j2g8rFqG6fPPa-FrjcqmjITFuyLi6XMRuYHGD9IR7XU0mQP1qSVKQkNgnw1lZLwLPQx-EuzXvyAMtvuIDyt7ZGM4zzWSW-S7WTfKtLleANwCeD9_z3Jj89HiE8B13P2CxR_R0E6Ode1zl69QLBY4b/s700/4.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="310" data-original-width="700" height="142" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6UO_1pN7ev9mq27uXUE4J_3ByM5UovJM6Q45ht90j2g8rFqG6fPPa-FrjcqmjITFuyLi6XMRuYHGD9IR7XU0mQP1qSVKQkNgnw1lZLwLPQx-EuzXvyAMtvuIDyt7ZGM4zzWSW-S7WTfKtLleANwCeD9_z3Jj89HiE8B13P2CxR_R0E6Ode1zl69QLBY4b/s320/4.png" width="320" /></a></div><br /><span style="font-size: large;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> (b) <span>Density</span><span> </span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Density is defined as the ratio of the mass of an object to its volume; usually it is expressed in kg/</span><span style="font-size: medium;">m</span><sup style="text-align: right;">3</sup><span style="font-size: medium;"> or g/c</span><span style="font-size: medium;">m</span><sup style="text-align: right;">3</sup><span style="font-size: medium;">. Mathematically,</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDeGwSh-7hn9g2Fa2cL8aBdd4K4u-JHkBdAMUFDhZB1PGmqr78AvW16lJZn1l3zQZnCfPNipkuvbz4E9PtDPmXaM88Rd6ArpUsl0cpQaGL6dcts5pTuwyMsxzrYrb7h1dADLGaiunJUM6u7PclAQz-FiIOclNzHnEzL8FTWoGE8bVt9BnsZB-__CLmYbma/s673/5.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="301" data-original-width="673" height="143" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDeGwSh-7hn9g2Fa2cL8aBdd4K4u-JHkBdAMUFDhZB1PGmqr78AvW16lJZn1l3zQZnCfPNipkuvbz4E9PtDPmXaM88Rd6ArpUsl0cpQaGL6dcts5pTuwyMsxzrYrb7h1dADLGaiunJUM6u7PclAQz-FiIOclNzHnEzL8FTWoGE8bVt9BnsZB-__CLmYbma/s320/5.png" width="320" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> (c) Specific Gravity</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> The ratio of the density (or specific weight) of a substance to the density (or specific weight) of a standard fluid is called Specific </span><span>gravity or Relative density. The usual standard of comparison for solids and liquids is water at 4°C at atmospheric pressure. Gases are commonly compared to dry air, under standard conditions (0°C and atmospheric pressure).</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Specific gravity is not expressed in units, as it is purely a ratio. Mathematically,</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkNQZpirYu6LGMJDx_tW4VEQnaEFjYZcDWgpqO4CXTtKH__2FV9tqWPtb7cgwSGkr-nqg-kkCGY1n_jLrdmAjiNA98a3uUst3nW0QI5-ZHHjzYbJtIk2k8j1k_uSySfVkUANVYPzNahm_Op33tgHA42uWrRCv5LEaxQGCZglb5HFxEIaxLNlpoZBcaUAMP/s818/6.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="324" data-original-width="818" height="159" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkNQZpirYu6LGMJDx_tW4VEQnaEFjYZcDWgpqO4CXTtKH__2FV9tqWPtb7cgwSGkr-nqg-kkCGY1n_jLrdmAjiNA98a3uUst3nW0QI5-ZHHjzYbJtIk2k8j1k_uSySfVkUANVYPzNahm_Op33tgHA42uWrRCv5LEaxQGCZglb5HFxEIaxLNlpoZBcaUAMP/w400-h159/6.png" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u><b>Compressibility and Bulk Modulus</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Compressibility is the measure of change in volume of substance when pressure is exerted on it. Liquids are incompressible fluids. For each atmosphere increase in pressure, the volume of water would decrease 46.4 parts per million. The hydraulic brake systems used in most cars operate on the principle that there is essentially no change in the volume of the brake fluid when pressure is applied to this liquid.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> On the other hand, the volume of the gases can be readily changed by exerting an external pressure on the gas. An internal combustion engine provides a good example of the ease with which gases can be compressed.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The compressibility is the reciprocal of the bulk modulus. Compressibility is denoted by "k" and is expressed mathematically </span><span style="font-size: large;">as:</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4DCw1fRihnD-_72v2SiexEqTo5tAM6_4CxxGXdcxqBzxtEYvkFFQW2VUiyG348I0_8Q1cSOXdJqzkypLicOrWB2PCIp5QaBxCgYXMWJ3pk-gNHcm6weUwXfGqnF1lD3S8HvzyAqvoOFRelaW_07EUlexZ4ERkbLJTpj8M0yCbUHYhy-J6ZjaSD-wx4ToD/s171/7.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="145" data-original-width="171" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4DCw1fRihnD-_72v2SiexEqTo5tAM6_4CxxGXdcxqBzxtEYvkFFQW2VUiyG348I0_8Q1cSOXdJqzkypLicOrWB2PCIp5QaBxCgYXMWJ3pk-gNHcm6weUwXfGqnF1lD3S8HvzyAqvoOFRelaW_07EUlexZ4ERkbLJTpj8M0yCbUHYhy-J6ZjaSD-wx4ToD/s16000/7.png" /></a></div><br /><span style="font-size: large;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Where B is called the bulks modulus of elasticity and is defined as the ratio of change in pressure to volumetric strain (change in volume/original volume) over a fluid element. It is expressed as follows:</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA67Uq6wJ1yLGkaoo-ixSXoeQbwRwPAacpcejO1WbUw8ECrww4eoyDdNGYRQUO-foNy8Zl4egujGuLQJRH_VtoBAAMAk5pmk0BW6aIsZp-6cX6Tez08JyDAvrq6IpxBrPgmXFUlMQpIXTvNsNpLtZcq3VNJiPSx2gCraEeBnkgHQhkJULDUZuBTB0_JSTT/s852/content%20(5).png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="317" data-original-width="852" height="238" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA67Uq6wJ1yLGkaoo-ixSXoeQbwRwPAacpcejO1WbUw8ECrww4eoyDdNGYRQUO-foNy8Zl4egujGuLQJRH_VtoBAAMAk5pmk0BW6aIsZp-6cX6Tez08JyDAvrq6IpxBrPgmXFUlMQpIXTvNsNpLtZcq3VNJiPSx2gCraEeBnkgHQhkJULDUZuBTB0_JSTT/w640-h238/content%20(5).png" width="640" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u><b>Viscosity and Viscosity Index</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Viscosity is the measure of the internal friction of a fluid or its resistance to flow. A hydraulic fluid that is too viscous usually causes high-pressure drop, sluggish operation, low-mechanical efficiency, and high-power consumption. Low-viscosity fluids permit efficient low-drag operation, but tend to increase wear, reduce volumetric efficiency, and promote leakage.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Viscosity index is an arbitrary scale, which indicates how the viscosity of a fluid varies with changes in temperature. The higher the viscosity index, the lower the viscosity changes with respect to temperature and vice versa. Ideally, the fluid should have the same viscosity at very low temperatures as well as at high temperatures. In reality, this cannot be achieved. This change is common to all fluids. Heating tend to make fluids thinner and cooling makes them thicker.</span></p><p dir="ltr" style="text-align: left;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-84725218255995651352023-10-29T10:12:00.001-07:002023-10-29T10:12:41.401-07:00Bernoulli’s Equation<p><span style="font-size: medium;"> </span></p><span><span style="font-size: medium;"><a name='more'></a></span></span><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> It states that, for a non-viscous, incompressible fluid in steady flow, the sum of pressure, potential, and kinetic energies per unit volume is constant at any point. Mathematically, it can be expressed </span><span style="font-size: large;">as:</span></p><p dir="ltr" style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXj0OpFSnxORJCGpR9lNPX7PwJ934PVXQrUXvhgTb6_Z5vBeQtTR3XlQku8giDEhBmD72CrhsCFZ_ty4E7c8QIe9RxdUFaxBb9g4yXP8Pj1pbv6iyYKDup2YZR96tKL9Q2U0uKcvAKpCvDwlZuTj9l0AalN-M73GSI-abobRfBG4GlqpA-mk5CbtXOoU-8/s786/content%20(1).png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="404" data-original-width="786" height="206" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXj0OpFSnxORJCGpR9lNPX7PwJ934PVXQrUXvhgTb6_Z5vBeQtTR3XlQku8giDEhBmD72CrhsCFZ_ty4E7c8QIe9RxdUFaxBb9g4yXP8Pj1pbv6iyYKDup2YZR96tKL9Q2U0uKcvAKpCvDwlZuTj9l0AalN-M73GSI-abobRfBG4GlqpA-mk5CbtXOoU-8/w400-h206/content%20(1).png" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Bernoulli's principle states that in fluid flow, an increase in velocity occurs simultaneously with a decrease in pressure. It is named for the Dutch/Swiss mathematician/scientist Daniel Bernoulli; this phenomenon can be seen in airplane lift, a carburetor, the flow of air around the ball, etc.</span></p><p dir="ltr" style="text-align: justify;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-36561194552942080932023-10-26T09:04:00.003-07:002023-10-26T09:09:51.107-07:00Design Factors for Vocational Applications<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A commercial vehicle's design features are strongly influenced by its application. Depending on the operating conditions and job performed by the vehicle, a commercial vehicle has a partic- ular chassis, engine, powertrain, cab, suspension, and other spe- cific chassis equipment, as discussed in the following sections.</span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Chassis Frames</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The frame of a truck or bus are the vehicle's backbone, sup porting the vehicle loads of freight, equipment, and passen- gers. All equipment, such as engines, suspension systems, and the cab, ultimately must mount or attach to the frame. A frame must be sized and built appropriately to be capable of supporting the loads applied to it while adapting to the forces that bend and twist the frame, such as when the wheels hit bumps or potholes or the load shifts. Two main frame designs are:</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: #cc0000;">I.</span> Ladder</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: #cc0000;">2.</span> Tubular-type frames</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Ladder frames are the most common type of frame. They use two main large cross-sectional area side rails that are arranged longitudinally in the vehicle. Side rails are made from box or C-channel cold rolled alloyed steel. Smaller cross members join each of the side rails together using high-strength bolts or rivets to form a sub frame, providing good torsional strength to resist twisting and bending. The passenger compartment of the cab is attached to the frame after the frame is built. It does not require as much strength or rigidity since the frame pro- vides the primary structural strength. Many trucks, trailers, and buses are built on a ladder-type frame, such as the one shown in <span style="color: #800180;">FIGURE 1</span>. When used in semi-trailers, the floor mem- bers use dozens of small I-beams attached across two smaller main frame rails with each end attached to the trailer side plate. The king-pin area of the trailer frame usually has steel plate reinforcement.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Tubular frames do not use heavy side rails but, instead, as the name suggests, uses tubular steel to construct a ribbed structure of many lighter pieces of box sections. Attachment points for the engine and suspension system are present, but there is no separate passenger compartment cell like a ladder frame because the tubes integrate the compartment into a single frame structure. Structural integrity is provided by metal tubes, bulkheads, and box sections. Tubular frames are much more complex to build but are substantially lighter than ladder frames and provide much more room for passengers and freight (<span style="color: #800180;">FIGURE 2</span>). The passenger compartment area is safer since the frame cell is less likely to deform in an event, such as a vehicle roll-over.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBSTBWlttGvDMaJ409lE4i0IppBCbVLf-mKymfB-5rSm7B5Tiz0FU5ONaprRc1-lxM9Z7vMCwHQWA469mCzV0DyvneWrVlh8ibP0MlUaitHLCCsW3IwpwJ9xmRXvLS2btp1jxbSmmSypFvrzbTKmeyo8w6JI8KGeOHvye-LCyMz2CujDHfuGKoLhyphenhyphenM2bkj/s1156/content_002.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="524" data-original-width="1156" height="181" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBSTBWlttGvDMaJ409lE4i0IppBCbVLf-mKymfB-5rSm7B5Tiz0FU5ONaprRc1-lxM9Z7vMCwHQWA469mCzV0DyvneWrVlh8ibP0MlUaitHLCCsW3IwpwJ9xmRXvLS2btp1jxbSmmSypFvrzbTKmeyo8w6JI8KGeOHvye-LCyMz2CujDHfuGKoLhyphenhyphenM2bkj/w400-h181/content_002.jpg" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><b><span style="color: #2f9c6f; font-size: medium;">Engines</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Engines must have enough power to move heavy loads and accelerate up grades while providing good fuel economy. Diesel engines are primarily used for the following reasons:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: #cc0000;">1. </span>Superior fuel economy compared to any other internal combustion engine </span></p><p dir="ltr" style="text-align: justify;"><span style="color: #cc0000; font-size: large; text-align: left;">2. </span><span style="font-size: large; text-align: left;">Higher torque output, especially at low speeds</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #cc0000; font-size: large; text-align: left;">3.</span><span style="font-size: large; text-align: left;"> Durability-lasting three or more times longer than spark-ignition engines</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: #cc0000;">4.</span> Fewer maintenance requirements due to the absence of a spark-ignition system</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Battery-powered electric vehicles (BEVs) are rapidly becoming popular since they produce no noxious emissions at street levels. Very little maintenance is required by the electric motors too. Torque output is comparable or even greater than a diesel, but only at low speeds. Given the low cost of electricity to charge the batteries compared to the cost to purchase diesel fuel, BEVs are perceived to have low operating costs.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Torque is the most important factor in choosing an engine for commercial vehicles since it is torque that ultimately moves a load. Torque is the twisting force applied to the crank-shaft and then, finally, to the wheels. Torque is a function of cylinder pressure and it is the force that accelerates or moves a vehicle and its load.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Horsepower is a function of engine speed and torque. <span style="color: #3d85c6;">Horsepower </span>describes how fast the engine can turn while producing torque. A high-horsepower, high-torque engine can produce lots of power at high engine speeds. In contrast, a high-torque, low-horsepower engine cannot turn as fast while it produces torque. The following is an equation for horsepower:</span></p><p dir="ltr" style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMG3bpET5z7BWvnQgBUyZvuzOiE9kzUPPyeNbChwiHk13BqoTViVrr4VRbaZwlW9zO8O13v5sQvJAmpseryzbwxpN6RGVLyzRmuxBlwjzKoPY8iS3x_l1ulizG7jIqehfO4hMjm9IlHcwolbPLXir1sYkzitTCx_fUb01S7MNGndnhOPlc7Urik0nhFyjR/s289/1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="89" data-original-width="289" height="89" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMG3bpET5z7BWvnQgBUyZvuzOiE9kzUPPyeNbChwiHk13BqoTViVrr4VRbaZwlW9zO8O13v5sQvJAmpseryzbwxpN6RGVLyzRmuxBlwjzKoPY8iS3x_l1ulizG7jIqehfO4hMjm9IlHcwolbPLXir1sYkzitTCx_fUb01S7MNGndnhOPlc7Urik0nhFyjR/s1600/1.jpg" width="289" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: #3d85c6;"> Torque rise</span> is the difference between engine torque produced at rated speed (maximum engine rpm under load) and <span style="color: #3d85c6;">peak torque</span>, or maximum torque an engine can produce. Torque rise is expressed as a percentage of torque at the rated speed.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> To calculate torque rise, use the following equation:</span></p><p dir="ltr" style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8h70x2VC8Y1A-MVSc69R0vh3Ba6P6hVrb2573kHOcUMDG2GCU3OBodz0Kwh7PBPrXmspA1xGYWv8e-A6_zoZyGEP55ID0nNqVEDmE29GTLmhmE0B3BPrV0EHU41djCVR_uNgZpuFnNGDERaXNf_uycORMstrXEBm-1B3lwQVrbwsu4DJzjSgo6AVIDb31/s408/2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="64" data-original-width="408" height="50" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8h70x2VC8Y1A-MVSc69R0vh3Ba6P6hVrb2573kHOcUMDG2GCU3OBodz0Kwh7PBPrXmspA1xGYWv8e-A6_zoZyGEP55ID0nNqVEDmE29GTLmhmE0B3BPrV0EHU41djCVR_uNgZpuFnNGDERaXNf_uycORMstrXEBm-1B3lwQVrbwsu4DJzjSgo6AVIDb31/s320/2.jpg" width="320" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> For example, consider a vehicle with a peak torque rise of 1800 ft-lb (2440.5 N-m) and a torque at rated speed of 1200 ft-lb (1627 N-m). The percent torque rise is calculated as follows:</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjF-ve6ai2EWcQmS9lLcUzPSyn1JQC3Z1q7ZA7T_k-v2es7zjAlb7AKU6YhGlMQa3pqGgN7FGhYBWI4xRubvqWmGbqDs7DJIJXK_jcifjH7pydMYOUX2C83GZQ8p1U_WKTF4dp7w7TAydrjB-IgJyXd_UKjSIhyw4mn96RKiFyuDv0aB4meuXmN_a2Okip0/s329/3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="94" data-original-width="329" height="91" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjF-ve6ai2EWcQmS9lLcUzPSyn1JQC3Z1q7ZA7T_k-v2es7zjAlb7AKU6YhGlMQa3pqGgN7FGhYBWI4xRubvqWmGbqDs7DJIJXK_jcifjH7pydMYOUX2C83GZQ8p1U_WKTF4dp7w7TAydrjB-IgJyXd_UKjSIhyw4mn96RKiFyuDv0aB4meuXmN_a2Okip0/s320/3.jpg" width="320" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> High-torque-rise engines are used for line-haul applications and require a steep increase in torque, such as when climbing hills or steep grades. Vocational vehicles and those used in urban environments, such as transit buses or pick-up and delivery vehicles, use low-torque-rise engines, which have less peak torque but more torque is available over a wider engine operating range. <span style="color: #800180;">FIGURE 3</span> graphically illustrates the difference between low torque rise and high torque rise.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgF-TgV58RuHP1zV7R9Vs-LKQFBJLx1SbWuj-RLczi2q8rsnCt5b3amixjIs-LXP-WCuk0y4VE4G8tr7z0It-8ljyhyphenhyphenkazgW-oTl1vve4D5m6Z9O-2dB4LaWyeJok63mK8XIXhUV1llgaTpiakbO8_5JKSgKSjZFqhIEz4F7Z0pVW7aNZnI9lZm-JcQwJkV/s553/content_003.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="434" data-original-width="553" height="314" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgF-TgV58RuHP1zV7R9Vs-LKQFBJLx1SbWuj-RLczi2q8rsnCt5b3amixjIs-LXP-WCuk0y4VE4G8tr7z0It-8ljyhyphenhyphenkazgW-oTl1vve4D5m6Z9O-2dB4LaWyeJok63mK8XIXhUV1llgaTpiakbO8_5JKSgKSjZFqhIEz4F7Z0pVW7aNZnI9lZm-JcQwJkV/w400-h314/content_003.jpg" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> High-torque-rise engines allow the vehicle's driver to keep the vehicle in a higher gear range longer under load. This explains why high-torque-rise engines are only used in line- haul, on-highway trucks and buses. Torque is available in high- torque-rise engines only over a narrow speed range. At low speeds, little torque is available. However, its peak torque occurs at 10 to 15 mph (16.1 to 24.1 kph) or so below its cruising speed. This corresponds to about two-thirds of its maximum engine speed when the vehicle is correctly geared.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Low-torque-rise engines produce more consistent torque output over a wider engine rpm operating range. That makes them ideal for stop-start traffic and varying speed/load conditions. Torque output is not as high but more widely available.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Another difference between high-torque-rise and low-torque-rise engines is in their gearing. High-torque-rise vehicles generally use transmissions with fewer gears and wider ratio steps between gears. Low-torque-rise engines use transmissions with smaller ratio steps but need more gears.</span></p><p><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-23589907412698017922023-10-26T08:14:00.000-07:002023-10-26T08:14:52.955-07:00Vocational Applications of Commercial Vehicles<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A second major way to classify commercial vehicles is by the job (vocation) the vehicle performs. Common vocational appli</span><span style="font-size: large;">cations include:</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Pick-up and delivery</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Construction</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Fire service</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Heavy haul</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Intercity coach</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Line hal</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Logging</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Mining</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Refuse collection</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Rescue vehicles</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">School bus</span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: large;">■ </span><span style="font-size: medium;">Urban transit coach</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium; text-align: right;"></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> The following sections discuss these classifications in greater detail</span></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><b><span style="color: #2f9c6f; font-size: medium;">Pick-Up and Delivery</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;">Vehicles classified primarily for picking-up and delivering goods and services operate mostly within cities and/or suburban areas. A delivery vehicle typically travels three miles (4.8 km) between starts/stops with a 100% load capacity going and 40% load on return. Common vehicles included in this category are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Drop-bed auto haulers, as shown in <span style="color: #800180;">FIGURE 1</span></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: red; font-size: x-large;">■ </span>Moving vans</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: red; font-size: x-large;">■ </span>Refrigerated delivery trucks </span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: red; font-size: x-large;">■ </span>Beverage trucks</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: red; font-size: x-large;">■ </span>Municipal work trucks </span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: red; font-size: x-large;">■ </span>Flatbed trucks</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: red; font-size: x-large;">■ </span>Parcel delivery trucks </span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="color: red; font-size: x-large;">■ </span>Tow trucks and wreckers</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A common configuration of vehicle in North America for pick-up and delivery operations is the straight or conventional truck configuration, such as the one shown in <span style="color: #800180;">FIGURE 2</span>. A straight truck used in the city typically has a single axle because weight limits on city streets are much lower than those on major highways. In addition, a single axle helps the vehicle to be more maneuverable. A cab-over-engine (COE) design, which places the cab over the front axle and engine, is exclusively used in Europe where shorter vehicle length regulations prevail and roads are often narrow and twisty with sharp turns. While less comfortable to operate, COE designs provide exceptional maneuverability because the vehicle is shorter and visibility is improved (<span style="color: #800180;">FIGURE 3</span>).</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFwwlxzy8RloTuHTH2433sx_yPJKEe6dzQOtUZd2DYDXvf9sTRlEpqvQNJWJGQ2nuVCcjaTZSerNNRBCELdh250MVRYdp4-m7t0QLyy4Td9UVitEm5rcP7CJzg0xxeuVBzXOfoSg2aDz7hUpMOfRc5zdlXA183EcFfJ-XSoxFhyphenhyphenCCD14kyuLUEsFp4Drov/s1145/2-3-4.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="806" data-original-width="1145" height="450" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFwwlxzy8RloTuHTH2433sx_yPJKEe6dzQOtUZd2DYDXvf9sTRlEpqvQNJWJGQ2nuVCcjaTZSerNNRBCELdh250MVRYdp4-m7t0QLyy4Td9UVitEm5rcP7CJzg0xxeuVBzXOfoSg2aDz7hUpMOfRc5zdlXA183EcFfJ-XSoxFhyphenhyphenCCD14kyuLUEsFp4Drov/w640-h450/2-3-4.jpg" width="640" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> These vehicles use mid-bore diesel engines ranging from 3 to 7 L in displacement because of their superior fuel economy and superior low speed torque. This category of vehicle is the most adaptable vehicle for hybrid electric or battery electric operation since they do not travel far and return to a yard every day.</span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Construction</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Vehicles used in construction are primarily engaged in moving material to and from a job site. Operating conditions are gen- erally 90% of loaded operation on road surfaces made of con- crete, asphalt, gravel, crushed rock, or hard-packed dirt, and up to 10% of loaded operation in loose sand or on muddy job sites. Maximum grades encountered are 12%. As a result, construc- tion vehicles tend to use short-step, deep-reduction transmis- sions combined with low-torque-rise engines providing more consistent torque over a wider engine speed range torque. Loads are distributed equally from side to side.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Common vehicles included in this category are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Asphalt and gravel trucks, frequently referred to as dump trucks, as shown in <span style="color: #800180;">FIGURE 4</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Flatbed trucks hauling lumber and building supplies </span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Tank trucks, as shown in <span style="color: #800180;">FIGURE 5</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Landscape trucks, often referred to as tipper trucks out- side North America, as shown in <span style="color: #800180;">FIGURE 6</span> </span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Concrete mixers</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Snowplows</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_NBbhy4Ed93dANtXxmXa7K_6ZGxdoj5pUl-fXkClWCc8hCD5xyxU_KOcgzsZ8ZmkrkW0utdIRP6s6SGCKojgy0zLjjlHElKU9_7k0-_sZncFP8LEsUOCDiTQ9x5ApkjQrV-L9iVzTGRHrqEXYrUWM5b1LN0dF3VyE2aKCjCGewQWfRmlK6QljnGbiODwe/s1185/3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1185" data-original-width="577" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_NBbhy4Ed93dANtXxmXa7K_6ZGxdoj5pUl-fXkClWCc8hCD5xyxU_KOcgzsZ8ZmkrkW0utdIRP6s6SGCKojgy0zLjjlHElKU9_7k0-_sZncFP8LEsUOCDiTQ9x5ApkjQrV-L9iVzTGRHrqEXYrUWM5b1LN0dF3VyE2aKCjCGewQWfRmlK6QljnGbiODwe/w195-h400/3.jpg" width="195" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Fire Service</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> These vehicles are used to transport people and equipment to extinguish fires, paramedics, or for ambulance services. Annual distances traveled are typically less than 20,000 miles (32,187 km) per year. Typical vehicle routes are three miles (4.8 km) between start and stop. High deceleration stops are frequent.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Common vehicles in this category are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Aerial ladders and fire trucks, as shown in <span style="color: #800180;">FIGURE 7</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Pumpers tankers</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Aerial platforms and special applications, as shown in </span><span style="color: #800180; font-size: large;">FIGURE 8</span><span style="font-size: large;"> </span><span style="color: white; font-size: large;">FIGURE 9</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Ambulance/paramedic</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOUbaoaZk7Gmpy38dV72NC5SHsIdPX6YDgl-ka0jMjPrdJWZ-cUPzsQ-viZpAx9dzJ_3b-YE7IIeSnLDeodQ_lWFHgEmcUIAdajsxF2p2kP4E4fBQCKIZC9KqfN2xCyJMTRuwvPCfi5bPXF-0SgIyj03sAtk2Xq8IHFYNJcDZ1k_q1z6MN_spWV4jC-1mC/s647/4.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="647" data-original-width="581" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOUbaoaZk7Gmpy38dV72NC5SHsIdPX6YDgl-ka0jMjPrdJWZ-cUPzsQ-viZpAx9dzJ_3b-YE7IIeSnLDeodQ_lWFHgEmcUIAdajsxF2p2kP4E4fBQCKIZC9KqfN2xCyJMTRuwvPCfi5bPXF-0SgIyj03sAtk2Xq8IHFYNJcDZ1k_q1z6MN_spWV4jC-1mC/w359-h400/4.jpg" width="359" /></a></div><br /><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Heavy Haul</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Vehicles in the heavy-haul category move heavy equipment or materials at legal maximums for length, width, and weight. They may exceed those limits with special loading permits. Operation is mostly on road surfaces made of concrete, asphalt, and maintained gravel. Load weights are 100% of vehicle capacity going and empty on return. Vehicles in this classification require high horsepower, high-torque-rise engines with the ability to pull the heaviest loads. <span style="color: #800180;">FIGURE 9</span> illustrates a typical heavy- haul configuration.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical vehicle types in this category are: </span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Equipment-hauling flatbed trailers</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Steel haulers using high or low trailers</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwetDF2vwhjJaeUmKEZTu1l32j5JwZbFdOOoytDQRe5T1i3PrI4FD4-O3i50iIOTV5Tk6t4SCvDaS3_j9BlSdvnaRPwzVBYYOgdd2shnBPnrmo5FzEFAugOHlSfvWYzy5Ti_TSa0XeqtncU5RRiCc9D6Vm6ioZ12hOPVye80vWpkn-KrTpD7qNpyX3WiQt/s563/5.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="479" data-original-width="563" height="340" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwetDF2vwhjJaeUmKEZTu1l32j5JwZbFdOOoytDQRe5T1i3PrI4FD4-O3i50iIOTV5Tk6t4SCvDaS3_j9BlSdvnaRPwzVBYYOgdd2shnBPnrmo5FzEFAugOHlSfvWYzy5Ti_TSa0XeqtncU5RRiCc9D6Vm6ioZ12hOPVye80vWpkn-KrTpD7qNpyX3WiQt/w400-h340/5.jpg" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Intercity Coach</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> This category of vehicle transports people, and occasionally light freight, between cities and/or suburban areas. Intercity coaches travel on highway and in urban conditions accumulating high mileage on routes exceeding 30 miles (48.3 km) between start and stop.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical vehicle types in this category are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Tour coaches </span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Cross-country coaches</span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Line Haul</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Line-haul trucks move freight over long distances-generally over 60,000 miles/year (96,561 km/year). More than 30 miles (48.3 km) of distance between starting and stopping are typical for line-haul service. Straight trucks (trucks with only a box) use either single or tandem axles. Tractor-trailer combinations are most common.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical line-haul vehicles include:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>General freight trucks in either straight or tractor-trailer configurations, such as shown in <span style="color: #800180;">FIGURE 10</span> </span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;">Refrigerated food trucks</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Livestock tractor trailers</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Flatbed trailers, such as the one in <span style="color: #800180;">FIGURE 11</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Side curtains, as shown in <span style="color: #800180;">FIGURE 12</span>, that enable fast pallet unloading and loading with forklift trucks</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Line-haul trucks travel long distances with heavy loads and at high speeds. As a result, line-haul trucks have unique vehicle requirements for their engines, tires, suspensions, cab configu rations, etc.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh60ml3m9EpPpv4-wJEb_M0Ny2GDecR_qKcVp23bHjv8eQkLeyIy4q94gccNIOUvHl_14dhpC0vlPhtfML6wFlUDhR7gwVEmkzduO8nnaeqecamIOCeOk_Vc8ZGblD8aBSxxl0-cIa870g_M5Dnw_j_4rjR7fcyPsAmJAorTsqKN2mQsn-L2poRtxm0W-n2/s1185/1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="909" data-original-width="1185" height="306" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh60ml3m9EpPpv4-wJEb_M0Ny2GDecR_qKcVp23bHjv8eQkLeyIy4q94gccNIOUvHl_14dhpC0vlPhtfML6wFlUDhR7gwVEmkzduO8nnaeqecamIOCeOk_Vc8ZGblD8aBSxxl0-cIa870g_M5Dnw_j_4rjR7fcyPsAmJAorTsqKN2mQsn-L2poRtxm0W-n2/w400-h306/1.jpg" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Logging</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Logging trucks move shipments of wood logs, chips, and pulp between logging sites or to and from logging or paper mills. Logging trucks travel distances of 3 to 30 miles (4.8 to 48.3 km) between starts and stops. Mostly, they travel on road surfaces of concrete, asphalt, maintained gravel, crushed rock, or hard- packed dirt, but up to 10% of their loaded operation can occur on sandy or muddy job sites. Trucks are loaded to 100% capacity when delivering loads and empty when returning.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical logging vehicles are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Wood-chip haulers-either a straight truck or tractor and trailer</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Log-hauling tractor-trailer combinations, as shown in <span style="color: #800180;">FIGURE 13</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Logging trucks that operate in off-road conditions have unique requirements for specialized traction capabilities pro- vided by tires and drive axles. Heavy frames are also needed to resist damage from twisting and bending. Suspensions are designed to better handle severe off-road terrains while carry- ing the heaviest possible loads.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEis-_LqSAvkDSKKfSZ3s7b1WkSnvPcIMKxlQhkGV46r76rSyQLqpBrEiNjQyb2wW7YEApQ9r-QqBIztOdvzP4rGsotmg6d_MGYqiVKLyn0rJTWNGPXGFBqITMeuogTBZGAs0aEo0d_e4S1TXzmJM5BwkJ5U1kqWeVWGZI5cv_DJUePUyPr3cd-mbysCP8fa/s546/2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="217" data-original-width="546" height="159" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEis-_LqSAvkDSKKfSZ3s7b1WkSnvPcIMKxlQhkGV46r76rSyQLqpBrEiNjQyb2wW7YEApQ9r-QqBIztOdvzP4rGsotmg6d_MGYqiVKLyn0rJTWNGPXGFBqITMeuogTBZGAs0aEo0d_e4S1TXzmJM5BwkJ5U1kqWeVWGZI5cv_DJUePUyPr3cd-mbysCP8fa/w400-h159/2.jpg" width="400" /></a></div><br /><p></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Mining</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Mining operation trucks move rock, ore, gravel, and other min- erals. Average trip distances are 30 miles (48.3 km) between starting and stopping. While most operations are on-highway, up to 10% of distances traveled are over sandy or muddy job sites. The trucks are typically 100% loaded while delivering and empty on return trips.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical mining vehicle types are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Belly dump trailers</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Semi-end dump hopper trailer combinations</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The gravel hauler in <span style="color: #800180;">FIGURE 14</span> is an example of a mining application. The tilting dump box requires a power take-off to operate a hydraulic pump called a wet-line.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuIiivK17qz4BNDrSXdHADAJdUPQ-5km1NlU7MiLrE9gFjtQBfhbL7M2yIiNhy6uOXh3yBuDj0PVQCJ2zXZdTw_8iJ03nTcM3opfkOj_2s39YQQ5E4OiLveOsROk5ucYTjbqSRPN4JyMnUFRZN2RT2WXDDzvEGwLtEyP2rti8uWBGdoQ9qXf-mioJVo-Ia/s564/1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="446" data-original-width="564" height="316" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuIiivK17qz4BNDrSXdHADAJdUPQ-5km1NlU7MiLrE9gFjtQBfhbL7M2yIiNhy6uOXh3yBuDj0PVQCJ2zXZdTw_8iJ03nTcM3opfkOj_2s39YQQ5E4OiLveOsROk5ucYTjbqSRPN4JyMnUFRZN2RT2WXDDzvEGwLtEyP2rti8uWBGdoQ9qXf-mioJVo-Ia/w400-h316/1.jpg" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Refuse Collection</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Refuse vehicles, better known as garbage trucks, are used for pick-up and transportation of residential garbage or recycling materials. These vehicles encounter steep grades of up to 20% when they travel into landfill, transfer, or recycling sites. Refuse trucks typically have a high proportion of starts and stops for every mile traveled.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical refuse vehicles are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Front-/rear-/side-loading garbage trucks, as shown in </span><span style="font-size: large;"><span style="color: #800180;">FIGURE 15</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Sewer/septic/vacuum trucks</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Liquid waste haulers</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> To enable the greatest level of maneuverability and highest load capacity, refuse vehicles are typically built on low-entry, COE chassis.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcvBUDdVMnYMvc8jx4Ou762_JhWr2nWLXd4vcNAX1P_veWTslCh_6W0vnFry65C17QhK70O89l_kMutmcKUwmAVdwEBvXvOdMQb0eYqhRxNErdDR7H4bLLoP4uSJsCjfyExFaBMj772qNb7Y3bUnz7t24zeCwDP2Po0w9GvtqegKkq9sP4GB0iFyNVYnI7/s550/2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="345" data-original-width="550" height="251" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcvBUDdVMnYMvc8jx4Ou762_JhWr2nWLXd4vcNAX1P_veWTslCh_6W0vnFry65C17QhK70O89l_kMutmcKUwmAVdwEBvXvOdMQb0eYqhRxNErdDR7H4bLLoP4uSJsCjfyExFaBMj772qNb7Y3bUnz7t24zeCwDP2Po0w9GvtqegKkq9sP4GB0iFyNVYnI7/w400-h251/2.jpg" width="400" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Rescue Vehicles</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Rescue vehicles are specialized vehicles designed for rapid acceleration to crash sites on highways or airport tarmacs away from hydrant hookups. They are low mileage opera- tion vehicles with high horsepower engines and automatic transmissions.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical rescue vehicle types are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Airport Rescue Fire (ARF) Crash Rescue Fire (CRF)</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Rapid Intervention Vehicle (RIV) Emergency Service</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Some of the most powerful trucks with the fastest acceleration rates are crash-and-rescue trucks, as shown in <span style="color: #800180;">FIGURE 16</span>. These trucks are used to quickly extinguish fires at airports or on the highway because of accidents. As a result, crash-and- rescue trucks require high-speed capabilities while carrying heavy loads.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhx66ddVkIWCfuMEX0pFyBahu736n70t1QBXx65yl9skxP3dqdR-Cfx621d0tD7F1TNWiv8tS0cXgLxAZSxG8mHSGtxTp91eCtXoQvoPi2YdZVbOQvVYVZ_YX69VIJFeczrpB-4KYJuQ0D0Api7tKZw3uR8v-moNd9dQVoC_waIeWrlkEqfhylmkUVAgUO_/s559/content_005.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="240" data-original-width="559" height="171" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhx66ddVkIWCfuMEX0pFyBahu736n70t1QBXx65yl9skxP3dqdR-Cfx621d0tD7F1TNWiv8tS0cXgLxAZSxG8mHSGtxTp91eCtXoQvoPi2YdZVbOQvVYVZ_YX69VIJFeczrpB-4KYJuQ0D0Api7tKZw3uR8v-moNd9dQVoC_waIeWrlkEqfhylmkUVAgUO_/w400-h171/content_005.jpg" width="400" /></a></div><br /><p></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">School Bus</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> School buses are familiar people haulers that transport students to and from school or school-related events. Two stops per mile over mixed road surfaces are typical. School buses frequently operate under fully loaded capacity.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical school bus configurations are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Front-engine commercial chassis</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Front-or rear-engine integral coach, as shown in <span style="color: #800180;">FIGURE 17</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"></span></p><div class="separator" style="clear: both; text-align: center;"><span style="font-size: medium;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgneHivHTdVMKPrNo0KshyphenhyphenkMBVFsK3rJVV_z5nDyvvoVmkwmaWOx969zyhnPk32SPMe7XNTags5zeyYiL6QceJHOsz84dPFmActqQ7JsZQMXqcE6jcqRbhZg5IQJzqxJauY4GRRhrtWFRA9tXng5GYx1htVH_zBcMLE89QCGItmTfRrLIqRsiB09Xw5fdkQ/s567/1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="312" data-original-width="567" height="220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgneHivHTdVMKPrNo0KshyphenhyphenkMBVFsK3rJVV_z5nDyvvoVmkwmaWOx969zyhnPk32SPMe7XNTags5zeyYiL6QceJHOsz84dPFmActqQ7JsZQMXqcE6jcqRbhZg5IQJzqxJauY4GRRhrtWFRA9tXng5GYx1htVH_zBcMLE89QCGItmTfRrLIqRsiB09Xw5fdkQ/w400-h220/1.jpg" width="400" /></a></span></div><span style="font-size: medium;"><br /><span style="color: #800180;"><br /></span></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: #800180;"><br /></span></span></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2f9c6f; font-size: medium;">Urban Transit Coach</span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> As the name indicates, urban transit coaches are the city buses that transport people in and around cities or suburban areas. City buses operate on well-maintained highways and </span><span style="font-size: large;">residential streets made of asphalt or concrete. These units have a high frequency of starts and stops per mile-nine is considered typical.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Typical urban transit vehicles are:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>Airport shuttle buses</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: red; font-size: x-large; text-align: left;">■ </span>City transit buses, such as the one in <span style="color: #800180;">FIGURE 18</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"></span></p><div class="separator" style="clear: both; text-align: center;"><span style="font-size: medium;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcDAeRipMRdqaXiIo_7xlEPSuKwe5IVNvTnZaOvo3hvx_ErNTEHHHbrQrLH2BgRkTB8GqmRM2XDgYnmRhZo1vGGMO6C-_J46OREnvCrzgQcgQwJH-IqfzgGmL9ldW9A7A0P6q_qthFj25eFjg_leTy0MtN7A1Fc5eQXbjmg3BSh8RjkuUf-HpWiLgJd347/s553/2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="451" data-original-width="553" height="326" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcDAeRipMRdqaXiIo_7xlEPSuKwe5IVNvTnZaOvo3hvx_ErNTEHHHbrQrLH2BgRkTB8GqmRM2XDgYnmRhZo1vGGMO6C-_J46OREnvCrzgQcgQwJH-IqfzgGmL9ldW9A7A0P6q_qthFj25eFjg_leTy0MtN7A1Fc5eQXbjmg3BSh8RjkuUf-HpWiLgJd347/w400-h326/2.jpg" width="400" /></a></span></div><span style="font-size: medium;"><br /><span style="color: #800180;"><br /></span></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: #800180;"><br /></span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="color: #800180;"><br /></span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> These can come in a range of configurations, as shown in <span style="color: #800180;">FIGURE 19A</span> and <span style="color: #800180;">FIGURE 19B</span>, including double deckers and articulated or "bendy buses," as they are known in some countries.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitK6UCKireesrYKSnLFcEqkBIkl3AAkWQty3uJr9F56YK9aVEAB48L40q_v4arioRgFIr1C5lCXMFIKL8w5h52KDQlG6EIgtEYzl7AL8YZa0yBeSTNsC89UxvjCcUR8C0OeggRdkFWE2NUgjrz1LHvpTpECtgkBo3vUTWxIcXijpqxYJyrlDgEKfbuh3Y-/s894/4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="894" data-original-width="557" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitK6UCKireesrYKSnLFcEqkBIkl3AAkWQty3uJr9F56YK9aVEAB48L40q_v4arioRgFIr1C5lCXMFIKL8w5h52KDQlG6EIgtEYzl7AL8YZa0yBeSTNsC89UxvjCcUR8C0OeggRdkFWE2NUgjrz1LHvpTpECtgkBo3vUTWxIcXijpqxYJyrlDgEKfbuh3Y-/w249-h400/4.jpg" width="249" /></a></div><br /><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-39463238400443821892023-10-26T07:06:00.001-07:002023-11-07T03:48:13.901-08:00Classification by Operating Environment for Commercial Vehicles <p><span style="font-size: medium;"><br /></span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium; text-align: right;"> One of the most fundamental ways to classify commercial vehicles is by considering where a commercial vehicle performs its
primary job or vocation. Whether a vehicle operates only inside
a city with its frequent slow speed, stop and start conditions, off-
road, or at steady high speeds encountered during on-highway
operation, or in a combination of several operating environ-
ments, it has a major influence on vehicle design, operation,
and maintenance. The choice of its engine, how well it needs
to maneuver, its requirements for traction on various road or
off-road surfaces, and service and inspection intervals are just
a few variables affected by a vehicle's operating environment.
Each of these environments can also have further subcategories. For example, truck delivery, or even bus operations, can be
classified as regional or long haul. Regional operations return
more than 90% of vehicles back to a terminal in a single day.
Long-haul operations dispatch vehicles on trips lasting days-
and even weeks-before they return to a dispatch, loading, or
maintenance facility. </span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: large; text-align: right;"> </span><span style="font-size: large; text-align: right;"> </span><span style="font-size: medium;"><span style="text-align: right;">As already mentioned, road surface conditions also shape
the classification of vehicles. That is, vehicles can be classified
according to their suitability for travel on various road surfaces
or grades. As shown in <span style="color: #800180;">FIGURE </span>1, road grade is expressed as </span><span style="text-align: right;">a percentage and refers to the steepness of a hill. For example,
a 15% grade means the road drops or increases 15' (4.6 m) for
every 100' (30.5 m) traveled. </span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"></span></p><div class="separator" style="clear: both; text-align: center;"><span style="font-size: medium;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtzMADY0HNLbOvH70W7fgrpMjCs8kXJLcPOCn6p9v5i02lTcACULLUyfk1ALUvojTsZRCFOY-k-9ZOCWlioJ1Txd-kUsH2uePXz7AFwlpjHmZFJM20MrI5tDDOOmqOBNWMHICIQp7TG_1IainJ_8Z080OXiiv6bbQhyWahOz7Ts0b5Qe6UbeNA_MEhdpfP/s297/1.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="297" data-original-width="257" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtzMADY0HNLbOvH70W7fgrpMjCs8kXJLcPOCn6p9v5i02lTcACULLUyfk1ALUvojTsZRCFOY-k-9ZOCWlioJ1Txd-kUsH2uePXz7AFwlpjHmZFJM20MrI5tDDOOmqOBNWMHICIQp7TG_1IainJ_8Z080OXiiv6bbQhyWahOz7Ts0b5Qe6UbeNA_MEhdpfP/s1600/1.png" width="257" /></a></span></div><div class="separator" style="clear: both; text-align: center;"><span style="font-size: medium;"><br /></span></div><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span style="text-align: right;"><br /></span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium; text-align: right;"> Similarly, heavy-duty commercial vehicles can be classified according to how frequently they start and stop, or even
by their speed of travel. When classifying commercial vehicles
by operating conditions, five broad categories are used: Turn-
pike or interstate; on-highway; on-off-highway or mountainous
highway; off-highway; and urban. </span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2f9c6f; font-size: medium; text-align: right;"><b>Turnpike or Interstate </b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium; text-align: right;">Major highways are constructed differently than secondary
highways. The road materials, vehicle speeds, amount of stop-
and-go driving, and slope of the road crown are all factors that
determine a vehicle's suitability for turnpike or interstate appli-
cations. Those factors also influence the design, equipment,
and accessories an interstate vehicle uses. Vehicles classified for
operation on interstates, highways, or turnpikes are designed to
run on limited-access, well-maintained, multi-lane highways
made of excellent concrete or asphalt with maximum adverse
grades not in excess of 3%. </span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2f9c6f; font-size: medium; text-align: right;"><b>On-Highway </b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium; text-align: right;">Vehicles classified for use in on-highway operating conditions
operate exclusively on well-maintained major highways of
excellent concrete or asphalt construction. Roads are typically
level to rolling with occasional maximum grades to 8%. These
vehicles must operate within legal weight and dimensional lim-
itations and be capable to handle the steeper grades that may be
encountered.</span></p><p dir="ltr" style="text-align: left;"><b><span style="color: #2f9c6f;"><span style="font-size: medium;">On-/Off-Highway or Mountainous </span><span style="font-size: large;">Highway</span></span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;">Vehicles classified for on-/off-highway or mountainous high- way operating conditions should expect to spend 20% of their total operating time on secondary roads. These roads are normally made from good concrete or asphalt. Intermit tent grades of up to 12% may be encountered. The remain- ing time is traveled on off-highway roadways that are based on well-maintained crushed rock or similar material. Road grades in this class are more severe than on-highway opera tion. Operations are subject to legal weight and dimensional limitations.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2f9c6f; font-size: medium;"><b>Off-Highway</b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;">In this classification, vehicles spend more than 20% of their travel time on gravel roads or roads with a maintained crushed rock surface. The maximum grade can be as much as 12%, and grades of 8% are frequently encountered. This oper ation is not generally subject to legal weight or dimensional limitations.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2f9c6f; font-size: medium;"><b>Urban</b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;">Vehicles in this classification face operating conditions that are primarily within cities and suburban areas. That means these vehicles are subject to frequent stops and starts. Oper ation occurs on concrete, asphalt, and maintained gravel road surfaces. Because of the urban environment, vehicles in this class must have greater levels of maneuverability than is required of other classes. Vehicles in this class often use engines with a lower power output and transmissions with more steps.</span></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-4568154029397333042023-10-25T11:16:00.001-07:002023-10-25T11:16:43.914-07:00Overload hazards<p> </p><span><a name='more'></a></span><p><br /></p><p dir="ltr" style="text-align: justify;"> Overloads in an electrical system are hazardous because they can produce heat or arcing. Wires and other components in an electrical system or circuit have a maximum amount of current they can carry safely. If too many devices are plugged into a circuit, the electrical current will heat the wires to a very high temperature. If any one tool uses too much current, the wires will heat up.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMa_bZ7SgY8ZKCbUwOdnTN9noxTEkLawXRGg9hgqHJBJQUTJYzun4KLoW_ccL_x8VKD4Wdpr-xYUYgh69ZL-o0_RqLYfXpUDEY7Wr8DX_avuUc-quQ5Oq0-4Lh6m35wgJKvVHroL6awsMFd3C531BbS3xXbVWAvhF6IVD4b3pcIXG0ZDITQnL9_2at9orE/s223/Screenshot_4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="182" data-original-width="223" height="182" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMa_bZ7SgY8ZKCbUwOdnTN9noxTEkLawXRGg9hgqHJBJQUTJYzun4KLoW_ccL_x8VKD4Wdpr-xYUYgh69ZL-o0_RqLYfXpUDEY7Wr8DX_avuUc-quQ5Oq0-4Lh6m35wgJKvVHroL6awsMFd3C531BbS3xXbVWAvhF6IVD4b3pcIXG0ZDITQnL9_2at9orE/s1600/Screenshot_4.png" width="223" /></a></div><br /><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"> The temperature of the wires can be high enough to cause a fire. If their insulation melts, arcing may occur. Arcing can cause a fire in the area where the overload exists, even inside a wall.</p><p dir="ltr" style="text-align: justify;"> In order to prevent too much current in a circuit, a circuit breaker or fuse is placed in the circuit. If there is too much current in the circuit, the breaker “trips” and opens like a switch. If an overloaded circuit is equipped with a fuse, an internal part of the fuse melts, opening the circuit. Both breakers and fuses do the same thing: open the circuit to shut off the electrical current.</p><p dir="ltr" style="text-align: justify;"> If the breakers or fuses are too big for the wires they are supposed to protect, an overload in the circuit will not be detected and the current will not be shut off. Overloading leads to overheating of circuit components (including wires) and may cause a fire. You need to recognize that a circuit with improper overcurrent protection devices—or one with no overcurrent protection devices at all— is a hazard.</p><p dir="ltr" style="text-align: justify;"> Overcurrent protection devices are built into the wiring of some electric motors, tools, and electronic devices. For example, if a tool draws too much current or if it overheats, the current will be shut off from within the device itself. Damaged tools can overheat and cause a fire. You need to recognize that a damaged tool is a hazard.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3Mm06SXGbTW8_6B7_s37XSm1DQuzwA56ibs-5C8gKARt_lioMjhyX9tnQw_E0tiX8ysMJ2bxYBmwNOiIvB1OJ3PPHIlWM3A5XEO44VDPDLoKnn3i2_6V_qmU6fUxGiXyrDRDzCqgiNXwZ55gvjOD-ETjkwMv02iTSwAku06uv_lxLxRgHbXyzwK8tT59I/s296/Screenshot_5.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="234" data-original-width="296" height="234" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3Mm06SXGbTW8_6B7_s37XSm1DQuzwA56ibs-5C8gKARt_lioMjhyX9tnQw_E0tiX8ysMJ2bxYBmwNOiIvB1OJ3PPHIlWM3A5XEO44VDPDLoKnn3i2_6V_qmU6fUxGiXyrDRDzCqgiNXwZ55gvjOD-ETjkwMv02iTSwAku06uv_lxLxRgHbXyzwK8tT59I/s1600/Screenshot_5.png" width="296" /></a></div><br /><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><b><u>Notes:<br /></u></b></p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■</span> overload—too much current in a circuit</p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■</span> An overload can lead to a fire or electrical shock.</p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■ </span>circuit breaker—an overcurrent protection device that automatically shuts off the current in a circuit if an overload occurs</p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■</span> trip—the automatic opening (turning off) of a circuit by a GFCI or circuit breaker</p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■</span> fuse—an overcurrent protection device that has an internal part that melts and shuts off the current in a circuit if there is an overload</p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■</span> Circuit breakers and fuses that are too big for the circuit are dangerous.</p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■</span> Circuits without circuit breakers or fuses are dangerous.</p><p dir="ltr" style="text-align: left;"><span style="color: #38761d; font-size: large; text-align: justify;">■</span> Damaged power tools can cause overloads.</p><p dir="ltr" style="text-align: left;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-84457817328466929632023-10-25T11:01:00.003-07:002023-10-25T11:03:14.078-07:00Improper grounding hazards<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> When an electrical system is not grounded properly, a hazard exists. The most common OSHA electrical violation is improper grounding of equipment and circuitry. The metal parts of an electrical wiring system that we touch (switch plates, ceiling light fixtures, conduit, etc.) should be grounded and at 0 volts. If the system is not grounded properly, these parts may become energized. Metal parts of motors, appliances, or electronics that are plugged into improperly grounded circuits may be energized. When a circuit is not grounded properly, a hazard exists because unwanted voltage cannot be safely eliminated. If there is no safe path to ground for fault currents, exposed metal parts in damaged appliances can become energized.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Extension cords may not provide a continuous path to ground because of a broken ground wire or plug. If you contact a defective electrical device that is not grounded (or grounded improperly), you will be shocked. <span style="color: #800180;">You need to recognize that an improperly grounded electrical system is a hazard.</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Electrical systems are often grounded to metal water pipes that serve as a continuous path to ground. If plumbing is used as a path to ground for fault current, all pipes must be made of conductive material (a type of metal). Many electrocutions and fires occur because (during renovation or repair) parts of metal plumbing are replaced with plastic pipe, which does not conduct electricity. In these cases, the path to ground is interrupted by nonconductive material.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrn3qiLTHsnyBbJWc5UFlBLLuyQOpBjuPHca7tGpT0RgU7YANMphAvyCSRFIqUoWT9wodNV0A6XM7wxmqI-c2lPoafCC0SKp76KTQuPWluvHzIEP3LgP0HTG3WxUFM54N2RtpFji3cdr8Xm45gjEpzbLna15PCO_st3VQcgeZ0p-fb2Hg30WGZsCpLlc4K/s224/Screenshot_3.png" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="165" data-original-width="224" height="165" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrn3qiLTHsnyBbJWc5UFlBLLuyQOpBjuPHca7tGpT0RgU7YANMphAvyCSRFIqUoWT9wodNV0A6XM7wxmqI-c2lPoafCC0SKp76KTQuPWluvHzIEP3LgP0HTG3WxUFM54N2RtpFji3cdr8Xm45gjEpzbLna15PCO_st3VQcgeZ0p-fb2Hg30WGZsCpLlc4K/s1600/Screenshot_3.png" width="224" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p style="text-align: justify;"><span style="font-size: medium;"> <span style="color: #800180;">A ground fault circuit interrupter, or GFCI</span>, is an inexpensive lifesaver. GFCI’s detect any difference in current between the two circuit wires (the black wires and white wires). This difference in current could happen when electrical equipment is not working correctly, causing leakage current. If leakage current (a ground fault) is detected in a GFCI-protected circuit, the GFCI switches off the current in the circuit, protecting you from a dangerous shock. GFCI’s are set at about 5 mA and are designed to protect workers from electrocution. GFCI’s are able to detect the loss of current resulting from leakage through a person who is beginning to be shocked. If this situation occurs, the GFCI switches off the current in the circuit. GFCI’s are different from circuit breakers because they detect leakage currents rather than overloads.</span></p><p style="text-align: justify;"><span style="font-size: medium;"> Circuits with missing, damaged, or improperly wired GFCI’s may allow you to be shocked. <span style="color: #800180;">You need to recognize that a circuit improperly protected by a GFCI is a hazard.</span></span></p><p style="text-align: justify;"><span style="font-size: medium;"><u><b>Notes</b></u>:</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d; font-size: medium;">■ fault current—any current that is not in its intended path</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d; font-size: medium;">■ ground potential—the voltage a grounded part should have; 0 volts relative to ground</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d; font-size: medium;">■ If you touch a defective live component that is not grounded, you will be shocked.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d; font-size: medium;">■ GFCI—ground fault circuit interrupter—a device that detects current leakage from a circuit to ground and shuts the current off</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d; font-size: medium;">■ leakage current—current that does not return through the intended path but instead "leaks” to ground</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d; font-size: medium;">■ ground fault—a loss of current from a circuit to a ground connection</span></p><p><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-80694203286619672952023-10-25T10:45:00.005-07:002023-10-25T10:54:34.381-07:00Defective insulation hazards<p> </p><span><a name='more'></a></span><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: justify;"> Insulation that is defective or inadequate is an electrical hazard. Usually, a plastic or rubber covering insulates wires. Insulation prevents conductors from coming in contact with each other. Insulation also prevents conductors from coming in contact with people.</p><p dir="ltr" style="text-align: justify;"> Extension cords may have damaged insulation. Sometimes the insulation inside an electrical tool or appliance is damaged. When insulation is damaged, exposed metal parts may become energized ifa live wire inside touches them. Electric hand tools that are old, damaged, or misused may have damaged insulation inside. If you touch damaged power tools or other equipment, you will receive a shock. You are more likely to receive a shock if the tool is not grounded or doubleinsulated. (Double-insulated tools have two insulation barriers and no exposed metal parts.) <span style="color: #800180;">You need to recognize that defective insulation is a hazard.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgakEpeNe5rj62Mx7VfD_2HUqCw5mjUwTclHtH11-e-dAW2NRXWzEKILg8ZdEoryVuu-3wzBhVJp9Vs-bqzol7Qld2GjW1QQEAxs7IRRcz6H2nKoBgoPaC6HGbMeTeKH1dN_s9exMxZV31W_OMYe52gt8yp76moGMBTTZbgmXgg6iBuE2vxo1RlyXI6WvwL/s372/Screenshot_2.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="372" data-original-width="333" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgakEpeNe5rj62Mx7VfD_2HUqCw5mjUwTclHtH11-e-dAW2NRXWzEKILg8ZdEoryVuu-3wzBhVJp9Vs-bqzol7Qld2GjW1QQEAxs7IRRcz6H2nKoBgoPaC6HGbMeTeKH1dN_s9exMxZV31W_OMYe52gt8yp76moGMBTTZbgmXgg6iBuE2vxo1RlyXI6WvwL/s16000/Screenshot_2.png" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><br /><p dir="ltr" style="text-align: justify;"><b><u>Notes:</u></b></p><p style="text-align: justify;"><span style="color: #38761d;">■</span> <span style="color: #274e13;">If you touch a damaged live power tool, you will be shocked!</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d;">■</span><span style="color: #274e13;">A damaged live power tool that is not grounded or double-insulated is very dangerous!</span></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-92232237334139169892023-10-25T10:27:00.004-07:002023-10-25T10:27:41.300-07:00Simple or Canonical Form of Closed Loop System<p> </p><span><a name='more'></a></span><p><br /></p><p dir="ltr" style="text-align: justify;"><b>Key Point</b> : A block diagram in which, forward path contains only one block, feedback path contains only one block, one summing point and one take off point represents simple or canonical form of a closed loop system.</p><p dir="ltr" style="text-align: justify;"> This can be achieved by using block diagram reduction rules without disturbing output of the system. This form is very useful as its closed loop transfer function can be easily calculated by using standard result. This result is derived in this section.</p><p dir="ltr" style="text-align: justify;"> The simple form can be shown as in the <span style="color: #800180;">Fig. 1</span>.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEwXvjSC1tZ6UCv6DqFhZ0_MFPvKFb7XzF_t5o1r4rZbipBztIjp21x-AxrbOZKgZ0eSX3GeRqhBkWjceSBkj3-WFI1-R2CFmuebiDc-p4albtScUV01CzxgWi_46mNGTK8mfTtM5HcI2XL_4eQ7XDSNpU0cFnIYRxasu07RneiDSH2FwTTrHyNqfKBu-u/s281/Screenshot_3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="144" data-original-width="281" height="144" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEwXvjSC1tZ6UCv6DqFhZ0_MFPvKFb7XzF_t5o1r4rZbipBztIjp21x-AxrbOZKgZ0eSX3GeRqhBkWjceSBkj3-WFI1-R2CFmuebiDc-p4albtScUV01CzxgWi_46mNGTK8mfTtM5HcI2XL_4eQ7XDSNpU0cFnIYRxasu07RneiDSH2FwTTrHyNqfKBu-u/s1600/Screenshot_3.jpg" width="281" /></a></div><br /><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: left;">where, R(s)Laplace of reference input r(t)</p><p dir="ltr" style="text-align: left;"> C(s)Laplace of controlled output c(t)</p><p dir="ltr" style="text-align: left;"> E(s) →Laplace of error signal e(t)</p><p dir="ltr" style="text-align: left;"> B(s)Laplace of feedback signal b(t)</p><p dir="ltr" style="text-align: left;"> G(s)Equivalent forward path transfer function</p><p dir="ltr" style="text-align: left;"> H(s)→ Equivalent feedback path transfer function.</p><p dir="ltr" style="text-align: justify;"><b>Key Point:</b> G(s) and H(s) can be obtained by reducing complicated block diagram by using block diagram reduction rules.</p><p dir="ltr" style="text-align: justify;"><b><u><span style="color: #2b00fe;">1. Derivation of T.F. of Simple Closed Loop System</span></u></b></p><p dir="ltr" style="text-align: left;"> Referring to the <span style="color: #800180;">Fig. 1</span>, we can write following equations as,</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSsQcIR9BwD0S9t0DqZM8dVBgZf4K0Ksa-K_ORmgoa23Qg3mC4RcjatccZH6T_A_hOe0eOvEjdShdyGnQom0TnwOyY5IytyYnzUmQJoeviTMMh55SmnKVYl2FvI-VQt7nM0MQGkfWaaeJWG1sxTNo-Bq-vy2ATg1Yuu3i2C0bFs2h_rxJ9GYkTsN2Qsihx/s512/Screenshot_1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="311" data-original-width="512" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSsQcIR9BwD0S9t0DqZM8dVBgZf4K0Ksa-K_ORmgoa23Qg3mC4RcjatccZH6T_A_hOe0eOvEjdShdyGnQom0TnwOyY5IytyYnzUmQJoeviTMMh55SmnKVYl2FvI-VQt7nM0MQGkfWaaeJWG1sxTNo-Bq-vy2ATg1Yuu3i2C0bFs2h_rxJ9GYkTsN2Qsihx/s16000/Screenshot_1.png" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><p dir="ltr" style="text-align: left;"> Use + sign for negative feedback and Use - sign for positive feedback.</p><p dir="ltr" style="text-align: left;"> This can be represented as in the <span style="color: #800180;">Fig. 2</span>.</p><p dir="ltr" style="text-align: justify;"><b>Key Point</b>: This can be used as a standard result to eliminate such simple loops in a complicated system reduction procedure.</p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-13044587802144580062023-10-25T03:20:00.002-07:002023-10-25T03:20:54.441-07:00Block Diagram Models of Control Systems<p> </p><span><a name='more'></a></span><p><br /></p><p dir="ltr" style="text-align: justify;"> If a given system is complicated, it is very difficult to analyze it as a whole. With the help of transfer function approach, we can find transfer function of each and every element of the complicated system. And by showing connection between the elements, complete system can be splitted into different blocks and can be analyzed conveniently. This is the basic concept of block diagram representation.</p><p dir="ltr" style="text-align: justify;"> Basically block diagram is a pictorial representation of the given system. It is very simple way of representing the given complicated practical system. In block diagram, the interconnection of system components to form a system can be conveniently shown by the blocks arranged in proper sequence. It explains the cause and effect relationship existing between input and output of the system, through the blocks.</p><p dir="ltr" style="text-align: justify;"> To draw the block diagram of a practical system, each element of practical system is represented by a block. The block is called functional block. It means, block explains mathematical operation on the input by the element to produce the corresponding output. The actual mathematical function is indicated by inserting corresponding transfer function of the element inside the block.</p><p dir="ltr" style="text-align: justify;"><b>Note : </b> For a closed loop systems, the function of comparing the different signals is indicated by the summing point while a point from which signal is taken for the feedback purpose is indicated by take off point in block diagrams.</p><p dir="ltr" style="text-align: justify;"> All these summing points, blocks and take off points then must be connected exactly as per actual elements connected in the practical system. The connection between the blocks is shown by lines called branches of the block diagram. An arrow is associated with each and every branch which indicates the direction of flow of signal along the branch.</p><p dir="ltr" style="text-align: justify;"><b>Note: </b>The signal can travel along the direction of an arrow only.</p><p dir="ltr" style="text-align: justify;"> It cannot pass against the direction of an arrow. Hence <b>block diagram is an unilateral property of the system.</b></p><p dir="ltr" style="text-align: justify;"> In short any block diagram has following five basic elements associated with it:</p><p dir="ltr" style="text-align: left;"> 1) Blocks 2) Transfer functions of elements shown inside the blocks.</p><p dir="ltr" style="text-align: left;"> 3) Summing points 4) Take off points 5) Arrows.</p><p dir="ltr" style="text-align: left;"><b><u><span style="color: #2b00fe;">1. Illustrating Concept of Block Diagram Representation</span></u></b></p><p dir="ltr" style="text-align: justify;"> For example: Consider the liquid level system as shown in the <span style="color: #800180;">Fig. 1</span>. So to represent this by block diagram, identify the elements which are,</p><p dir="ltr" style="text-align: justify;"> i) Controller ii) Pneumatic valve iii) Tank iv) Float.</p><p dir="ltr" style="text-align: justify;"> In this system, the level of water is sensed by the float. Hence the float position acts as the feedback. According to the float position, with respect to desired level of water, the controller operates the pneumatic valve controlling the flow of water in the tank. When the required level is reached, controller operates the pneumatic valve in such a way that the flow of water in the tank, stops. If the output from the tank is taken i.e. the water from the tank is drained then the float position changes from the desired position and accordingly the controller operates the pneumatic valve to start the flow of water in the tank. </p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgItibZhRivXL9Ew-G5BW0FLgkR8v9uH7ghU5QxbzvTdgMGoRfRFctnr7e4hQvzJXD-ff3zVPAbIOf_Sm4WqjQbyEYXu9RB2KnLFtxaYWD-jPTtiMwuViiechVYhbdLrfUlF1hf0g-1a2jPumTpjBihyphenhyphenbqHa6UObTxtQwFdm8dd4bFJ6aWSKogCwE4YJQOm/s311/Screenshot_10.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="185" data-original-width="311" height="185" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgItibZhRivXL9Ew-G5BW0FLgkR8v9uH7ghU5QxbzvTdgMGoRfRFctnr7e4hQvzJXD-ff3zVPAbIOf_Sm4WqjQbyEYXu9RB2KnLFtxaYWD-jPTtiMwuViiechVYhbdLrfUlF1hf0g-1a2jPumTpjBihyphenhyphenbqHa6UObTxtQwFdm8dd4bFJ6aWSKogCwE4YJQOm/s1600/Screenshot_10.jpg" width="311" /></a></div><br /><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"> Hence indicating all the elements by blocks, the block diagram of the system can be developed as in the <span style="color: #800180;">Fig. 2</span>.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj51o_1uuN7y6jHPWcZ6QGp6PDb2RiVb_pCk-DvXGJOh61s3g7mcnYqkwB4NjEan75AI73EPOhTSCJ-DK1Eikz-XEg424cgXXEgvjbET71JzUY422xMOYHGuEnvNHozJm7rlFN5WantalW6Phpp2IBE0Ec8zIuNgrMjFldIYAJepmQz5ylD5nlYu2CNqCI9/s384/Screenshot_11.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="196" data-original-width="384" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj51o_1uuN7y6jHPWcZ6QGp6PDb2RiVb_pCk-DvXGJOh61s3g7mcnYqkwB4NjEan75AI73EPOhTSCJ-DK1Eikz-XEg424cgXXEgvjbET71JzUY422xMOYHGuEnvNHozJm7rlFN5WantalW6Phpp2IBE0Ec8zIuNgrMjFldIYAJepmQz5ylD5nlYu2CNqCI9/s16000/Screenshot_11.jpg" /></a></div><br /><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><b><u><span style="color: #800180;">2. Advantages of Block Diagram</span></u></b></p><p dir="ltr" style="text-align: left;"> The various advantages of block diagram representation are,</p><p dir="ltr" style="text-align: left;"> 1) Very simple to construct the block diagram for complicated systems.</p><p dir="ltr" style="text-align: left;"> 2) The function of individual element can be visualised from block diagram.</p><p dir="ltr" style="text-align: justify;"> 3) Individual as well as overall performance of the system can be studied by using transfer functions shown in the block diagram.</p><p dir="ltr" style="text-align: justify;"> 4) Overall closed loop T.F. can be easily calculated by using block diagram reduction rules.</p><p dir="ltr" style="text-align: left;"><b><span style="color: #800180;"><u>3. Disadvantages</u></span></b></p><p dir="ltr" style="text-align: left;"> The various disadvantages of block diagram representation are,</p><p dir="ltr" style="text-align: left;"> 1) Block diagram does not include any information about the physical construction of the system.</p><p dir="ltr" style="text-align: justify;"> 2) Source of energy is generally not shown in the block diagram. So number of different block diagrams can be drawn depending upon the point of view of analysis. So block diagram for given system is not unique.</p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-74293552178424204862023-10-25T02:37:00.002-07:002023-10-25T02:41:17.667-07:00Linear Approximations of Linear Systems<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> There are various nonlinearities in practice such as friction, deadzone, saturation, hysterisis etc. None of the practical systems is linear in nature. But most of the important mathematical methods are available for the analysis of linear systems only. Hence practically a compromise is done between ease of analysis and accuracy of analysis and a nonlinear system is treated as linear under linear approximations. This technique of making nonlinear system approximations, This technique of making nonlinear system linear under linear approximations is called linearization technique.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium; text-align: left;"> Thus whenever situation justifies, the linearization technique is used to analyse the nonlinear systems.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The common situation where linearization can be used is a smooth curve which differs very little from the point of tangency. Hence in the narrow region near the point of tangency a nonlinear curve can be approximated as a straight line for the analysis purpose. This situation is very common in control systems in which the purpose of the systems is to keep controlled variable very close to its desired value. Hence the range of variation of a controlled variable is narrow and close to a set point and hence can be assumed linear. But if the system is essentially following a curve then we can analyze the system by linearizing it at several points along the curve.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Consider a general control system with x(t) as the input while y(t) as the output. The variation of an output variable is given by a function f(x) as shown in the <span style="color: #800180;">Fig. 1</span>. The relationship is nonlinear but is continuous.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiz0Mun6CzQJE_aK9Hqji9DyiqQYjowAWCzh6GKOMfiiO8fU3pOmT6MmSfNdybvReRPoY0K-m-f0csB1S763w451YIHl0-WfC-am7_jj1auiSGGUJtPSUA3YtZlaubvC1UwDz46I6e6w79NFZ4-oX6ZbEVDLhZo62K4DA0PNRhEzIIqMlnMeuRaIfdcpget/s235/Screenshot_1.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="169" data-original-width="235" height="169" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiz0Mun6CzQJE_aK9Hqji9DyiqQYjowAWCzh6GKOMfiiO8fU3pOmT6MmSfNdybvReRPoY0K-m-f0csB1S763w451YIHl0-WfC-am7_jj1auiSGGUJtPSUA3YtZlaubvC1UwDz46I6e6w79NFZ4-oX6ZbEVDLhZo62K4DA0PNRhEzIIqMlnMeuRaIfdcpget/s1600/Screenshot_1.jpg" width="235" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Expansion of the equation y = f(x) into a Taylor's series about the normal operating <span style="text-align: left;">point (x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">n</sub><span style="text-align: left;">, </span><span style="text-align: left;">y</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">n</sub><span style="text-align: left;">) is given by,</span></span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgN0IOcMyM4Uv2lfT75fOprOTu36FYrpZX3SIZM_nyDA8vMmSAFr9mLdax6Gy41trNlRNI6xEVKf0PTlHB_FWGA49s0dr5KrF4XSMol6mPI8chz00fhwgvIxW4dC88q-14WLVEIWUX9dYna-3ZQ4EMM-IKWBu58wgRYg45E91yADnvNli0twMjL2XfIK115/s451/Screenshot_2.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="55" data-original-width="451" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgN0IOcMyM4Uv2lfT75fOprOTu36FYrpZX3SIZM_nyDA8vMmSAFr9mLdax6Gy41trNlRNI6xEVKf0PTlHB_FWGA49s0dr5KrF4XSMol6mPI8chz00fhwgvIxW4dC88q-14WLVEIWUX9dYna-3ZQ4EMM-IKWBu58wgRYg45E91yADnvNli0twMjL2XfIK115/s16000/Screenshot_2.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><div class="separator" style="clear: both; text-align: center;"><span style="font-size: medium;"><br /></span></div><span style="font-size: medium;"><br /><span style="text-align: left;"><br /></span></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium; text-align: left;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> It is assumed that from the point of tangency the variation is very small hence (x - <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">n</sub>) about the normal operating point is very small. Hence higher order terms of (x - <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">n</sub>) can be easily neglected which gives,</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmvNKwaSQewwnVwu_CsD3ArKkmNqRfhHAeURdC3xfnxkDwizzLT3t1T9KV6XN1abjPih8jCvM9L94Bn4hes3j8nXn-co_v-L2Il3G7y-khdpILCoHdoZDW8hlD2W3mNTg_QbdmEbrJTi4Av9QdG_hXq0kQMJPWmu9nHe75Om8w99vxDYrLdbKl0-GR1X91/s522/Screenshot_3.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="77" data-original-width="522" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmvNKwaSQewwnVwu_CsD3ArKkmNqRfhHAeURdC3xfnxkDwizzLT3t1T9KV6XN1abjPih8jCvM9L94Bn4hes3j8nXn-co_v-L2Il3G7y-khdpILCoHdoZDW8hlD2W3mNTg_QbdmEbrJTi4Av9QdG_hXq0kQMJPWmu9nHe75Om8w99vxDYrLdbKl0-GR1X91/s16000/Screenshot_3.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><div class="separator" style="clear: both; text-align: center;"><span style="font-size: medium;"><br /></span></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The equation represents a straight line of the form y = mx + c which is perfectly linear.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNiV5cG0S-ZJ0Fdj5nGdq2ww7dZbK-M1Im7UiTF2V4YtDPqvYKbya_91ULk30BMqrh8KBvyzauj4t42dObV-MIQexaRCt22BaMR9aLCdj8E-YsD7vuFw_F8wqKRd0LxCxC1eq0tfgU4Wbs0ENjpSgs781xEZPcDLVW5pA9C-irMmUTy1j2Ji4w7x8NoeJ8/s512/Screenshot_4.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="27" data-original-width="512" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhNiV5cG0S-ZJ0Fdj5nGdq2ww7dZbK-M1Im7UiTF2V4YtDPqvYKbya_91ULk30BMqrh8KBvyzauj4t42dObV-MIQexaRCt22BaMR9aLCdj8E-YsD7vuFw_F8wqKRd0LxCxC1eq0tfgU4Wbs0ENjpSgs781xEZPcDLVW5pA9C-irMmUTy1j2Ji4w7x8NoeJ8/s16000/Screenshot_4.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p style="text-align: justify;"><span style="font-size: medium;"> If the output variable y depends on multiple input variables <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">1</sub>, <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">2</sub>, <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">3</sub>, .....<span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">m</sub> i.e.y= f(<span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">1</sub>, <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">2</sub>, <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">3</sub>........<span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">m</sub>) then the linear approximation for y can be achieved by this equation into Taylor's series about the operating point (<span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">1n</sub>, <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">2n</sub>, <span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">3n</sub>, ..........<span style="text-align: left;">x</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">mn</sub>, y<sub style="font-family: Calibri, "sans-serif"; text-align: right;">n</sub>) and neglecting all higher order derivative terms. Such a linearization gives,</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA5hs5XX8-zQRZX4SVwcYFqa8I2i1I0lF5j7sPPnkoqsoMYRktfgvauSDN2mXv6r5Shxm1ooQpfI7iq0hDHA-CiQNBbCbn6tLVYOu35CN3KwdNvQW0dDV7RIh2-xWOYltCOU2dxV6-mcqxXw5BONo6jRRh7L5QpNGISk98NnTe6d0nrCrKaojxU36x67TM/s409/Screenshot_8.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="163" data-original-width="409" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjA5hs5XX8-zQRZX4SVwcYFqa8I2i1I0lF5j7sPPnkoqsoMYRktfgvauSDN2mXv6r5Shxm1ooQpfI7iq0hDHA-CiQNBbCbn6tLVYOu35CN3KwdNvQW0dDV7RIh2-xWOYltCOU2dxV6-mcqxXw5BONo6jRRh7L5QpNGISk98NnTe6d0nrCrKaojxU36x67TM/s16000/Screenshot_8.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-60068380931942025542023-10-25T01:59:00.001-07:002023-10-25T02:03:23.378-07:00A.C. Servomotors<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Most of the servomotors used in low power servomechanisms are a.c. servomotors. The a.c. servomotor is basically two phase induction motor. The output power of a.c. servomotor varies from fraction of watt to few hundred watts. The operating frequency is 50 Hz to 400 Hz.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><b><u>1. Construction</u></b></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> It is mainly divided into two parts namely stator and rotor.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The stator carries two windings, uniformly distributed and displaced by 90°, in space. One winding is called main winding or fixed winding or reference winding. This is excited by a constant voltage a.c. supply. The other winding is called control winding. It is excited by variable control voltage, which is obtained from a servoamplifier. This voltage is 90° out of phase with respect to the voltage applied to the reference winding. This is necessary to obtain rotating magnetic field. The schematic stator is shown in the <span style="color: #800180;">Fig. 1</span>.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> </span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0s_5tLOHiNBMTpLKxK4rrz72jns4AkftjBk0zwLzsRUba77AIyLnduAw_deXm_6J4YkcQR5ncnncUTKCXss58Vg7dnOI8bz504gMrhywibV5S4B-kC-mCpb6tTzWo_qRQeLoZyTjxQ7tKKlRouxgItJtJWQx29IPiwpwlalua3Asqq5O4PNfyccJZp9kn/s255/Screenshot_5.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="147" data-original-width="255" height="147" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0s_5tLOHiNBMTpLKxK4rrz72jns4AkftjBk0zwLzsRUba77AIyLnduAw_deXm_6J4YkcQR5ncnncUTKCXss58Vg7dnOI8bz504gMrhywibV5S4B-kC-mCpb6tTzWo_qRQeLoZyTjxQ7tKKlRouxgItJtJWQx29IPiwpwlalua3Asqq5O4PNfyccJZp9kn/s1600/Screenshot_5.jpg" width="255" /></span></a></div><span style="font-size: medium;"><br /> </span><p></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><u><b>2. Rotor</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The rotor is generally of two types. The one is usual squirrel cage rotor. This has small diameter and large length. Aluminium conductors are used to keep weight small. Its resistance is very high to keep torque-speed characteristics as linear as possible. Air gap is kept very small which reduces magnetizing current. This cage type of rotor is shown with skewed bars in the <span style="color: #800180;">Fig. 2 (a)</span>. The other type of rotor is drag cup type. There are two air gaps in such construction. Such a construction reduces inertia considerably and hence such type of rotor is used in very low power applications. The aluminium is used for the cup construction. The construction is shown in the <span style="color: #800180;">Fig. 2 (b)</span>.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2UJiK1PbFVm2wXwNpCjaaE36cCBI-51LnOFuVc4h0JSJevxND2DBX8pJ1iWlazw_0BvRoFyxELOkx_xaWHEXlyWPVLPcEOycVCyOsdgKzzzSb-A4wvjbnP4w1fWodOyPvutWycr3IoIQnktboLE2jdkGqtElfxHThM4r3tyQ6HAUduJr0o0duSwQ5RFMZ/s474/Screenshot_6.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="173" data-original-width="474" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2UJiK1PbFVm2wXwNpCjaaE36cCBI-51LnOFuVc4h0JSJevxND2DBX8pJ1iWlazw_0BvRoFyxELOkx_xaWHEXlyWPVLPcEOycVCyOsdgKzzzSb-A4wvjbnP4w1fWodOyPvutWycr3IoIQnktboLE2jdkGqtElfxHThM4r3tyQ6HAUduJr0o0duSwQ5RFMZ/s16000/Screenshot_6.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u><b>3. Torque-Speed Characteristics </b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The torque-speed characteristics of a two phase induction motor, mainly depends on the ratio of reactance to resistance. For small X to R ratio i.e. high resistance low reactance motor, the characteristics is much more linear while it is non-linear for large X to R ratio as shown in the <span style="color: #800180;">Fig.3</span>.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg-OSi2S3bXpRzA3H7o1YLR38_95sFCFd9XB2-2_9vvcWWLdgXMbqYVGDmrdbQnV20aYxImtI9fS-t1LOi05dotoOcIdpbAgJPFEz-aZNN9PUSB7evLX94uc3eR_CSShtvU2HyVnlPbHpl95tMZirqtQYQRseUl97YUMOYpaa2u3w0RMg5JwVk8-VaTk09/s218/Screenshot_7.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="171" data-original-width="218" height="171" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjg-OSi2S3bXpRzA3H7o1YLR38_95sFCFd9XB2-2_9vvcWWLdgXMbqYVGDmrdbQnV20aYxImtI9fS-t1LOi05dotoOcIdpbAgJPFEz-aZNN9PUSB7evLX94uc3eR_CSShtvU2HyVnlPbHpl95tMZirqtQYQRseUl97YUMOYpaa2u3w0RMg5JwVk8-VaTk09/s1600/Screenshot_7.jpg" width="218" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> In practice, design of the motor is so as to get almost linear torque-speed characteristics. The <span style="color: #800180;">Fig. 4</span> shows the torque-speed characteristics for various control voltages. The torque varies almost linearly with speed. All the characteristics are equally spaced for equal increments of control voltage. It is generally operated with low speeds.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjep5plOlXMuqC3akwZ_yD1E1N1PxZzoesY9uyYr6qrxDpc_GY21N0HO02qcGakoJ_LYY2ZHF1nBSXBqMb8ZYxaWTbFYIBIzkuFNHnr84Fq3dXETcxfJ_VVVc0I8aujWOpBW6ngGL71AvJ2maJdE0wFtHXaN75nunxQtgrEH55csjGD9yJcuwGW7j2zfaIo/s227/Screenshot_9.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="178" data-original-width="227" height="178" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjep5plOlXMuqC3akwZ_yD1E1N1PxZzoesY9uyYr6qrxDpc_GY21N0HO02qcGakoJ_LYY2ZHF1nBSXBqMb8ZYxaWTbFYIBIzkuFNHnr84Fq3dXETcxfJ_VVVc0I8aujWOpBW6ngGL71AvJ2maJdE0wFtHXaN75nunxQtgrEH55csjGD9yJcuwGW7j2zfaIo/s1600/Screenshot_9.jpg" width="227" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><u><b><span style="color: #2b00fe; font-size: medium;">4. Features of A.C. Servomotors</span></b></u></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> The a.c. servomotor has following features:</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> i) Light in weight. ii) Robust construction. iii) Reliable and stable operation. iv) Smooth and noise free operation v) Large torque to weight ratio vi) Large R to X ratio i.e. small X to R ratio. vii) No brushes or slip rings hence maintenance free. viii) Simple driving circuits.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><b><u><span style="color: #2b00fe; font-size: medium;">5. Applications</span></u></b></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;">Due to the above features it is widely used in instrument servomechanisms, remote positioning devices, process control systems, self balancing recorders, computers, tracking and guidance systems, robotics, machine tools etc.</span></p><p dir="ltr" style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u><b>6. Transfer Function of A.C. Servomotors</b></u></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> The various approximations to derive transfer function are,</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> i) A servomotor rarely operates at high speeds. Hence for a given value of control voltage, T α N characteristics are perfectly linear.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> ii) In order that Tα N characteristics are directly proportional to voltage applied to its control phase, we assume T α N characteristics are straight lines and equally spaced.</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> Torque at any speed 'N' is,</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgszNOhaDQOG3PfVDL9wFK6i-Luo_VMNWhI8UvkWJ1fUdNSrrIiyCKKz2oS7xR-EXsCYnKht6_aOEY6CB2bwlWJY0GyObTMIc3wv_9uGubXSoDmkw1Hgip393ZuW-FEXzi4Nk2fRNdDUopp5yP4uvZD0_Km4NThMG2M0rkLoJ6fNQBWZeNVijDOxAtq4Ram/s446/Screenshot_10.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="34" data-original-width="446" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgszNOhaDQOG3PfVDL9wFK6i-Luo_VMNWhI8UvkWJ1fUdNSrrIiyCKKz2oS7xR-EXsCYnKht6_aOEY6CB2bwlWJY0GyObTMIc3wv_9uGubXSoDmkw1Hgip393ZuW-FEXzi4Nk2fRNdDUopp5yP4uvZD0_Km4NThMG2M0rkLoJ6fNQBWZeNVijDOxAtq4Ram/s16000/Screenshot_10.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> where d<span face=""Arial","sans-serif"" style="line-height: 115%; mso-ansi-language: EN-US; mso-bidi-language: AR-EG; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin;">θ</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">m</sub>/dt is speed of motor.</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> If load consists inertia Im and friction Bm we can write,</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq5AsXi_cAncybREBRHmc4qqqvUSceWwGSW9LSBfNsH_F6E1R84fFE9fFJHGBJQWJM-y_YIW46tFtrNXRBQPhnhkDsnwK5ApPoA_4BmZELzJ40llgS8t4H_3hg7IBVSEFDzdxwXwi5kQKnT_fJ4Ju4jLqgvdGKnoVmvazH60DKjZ5KSiOXr8UEioTBSplw/s454/Screenshot_11.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="23" data-original-width="454" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq5AsXi_cAncybREBRHmc4qqqvUSceWwGSW9LSBfNsH_F6E1R84fFE9fFJHGBJQWJM-y_YIW46tFtrNXRBQPhnhkDsnwK5ApPoA_4BmZELzJ40llgS8t4H_3hg7IBVSEFDzdxwXwi5kQKnT_fJ4Ju4jLqgvdGKnoVmvazH60DKjZ5KSiOXr8UEioTBSplw/s16000/Screenshot_11.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> Now Laplace transform of equation (1) is</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6yesL1BtCGK0E_-l0EQ2zgBDOUXa9BVvj-4wv4c11u-I6q7kGQBfwLTDj_fu6mqE9fJMgIUq-uOzN7n052tZaZNQfB7x-LuQSL_QnKk8LWQ4bsExyIt3w_9X-HQei4uo0ehbuFsoJRDQhHTSdWr8iMk5rGlz7ypgWQ-TfbUJ9gdbMyOCSuRegIrXSBgJC/s455/Screenshot_12.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="25" data-original-width="455" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6yesL1BtCGK0E_-l0EQ2zgBDOUXa9BVvj-4wv4c11u-I6q7kGQBfwLTDj_fu6mqE9fJMgIUq-uOzN7n052tZaZNQfB7x-LuQSL_QnKk8LWQ4bsExyIt3w_9X-HQei4uo0ehbuFsoJRDQhHTSdWr8iMk5rGlz7ypgWQ-TfbUJ9gdbMyOCSuRegIrXSBgJC/s16000/Screenshot_12.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> Equating equations (2) and (3)</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwYBXYT_FyOvcRuNF8RW-qHs9lLfKp82mW_WBY7fep-tVUFGE6AwYHcmvQAXu93OpMXoTDTm4k74lfFFc-Ey2XAvp6ppoNu57SL_DZdrtkI-HyDVOMhzitiEPO3ic62Iy80LcfxQRFUl-P08zXTchZp6dx5_vxHhsRa8Uq4Ct10QaMpK0FXrIg5qNmaIlk/s407/Screenshot_13.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="252" data-original-width="407" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwYBXYT_FyOvcRuNF8RW-qHs9lLfKp82mW_WBY7fep-tVUFGE6AwYHcmvQAXu93OpMXoTDTm4k74lfFFc-Ey2XAvp6ppoNu57SL_DZdrtkI-HyDVOMhzitiEPO3ic62Iy80LcfxQRFUl-P08zXTchZp6dx5_vxHhsRa8Uq4Ct10QaMpK0FXrIg5qNmaIlk/s16000/Screenshot_13.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> Single flow graph of a.c. servomotor is as shown in the Fig. 5.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBryrNJGOLj-PSQirjnaRYC85BMq4_AzElPA0ZTcIJf8NNPrvPQ81TDx6juBLLo1ttM7Xd4Xvuhg73j-YAJJEmRZpA19SJcWjTMA0CQpVAFU64gIcq8hT5wx3bszgLa8QxSCWGxF45PEp6Altl8lDv_lG0YyesIhcbM3_z_9aHOHMdnVmr5sMmCzHZMU7w/s267/Screenshot_14.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="113" data-original-width="267" height="113" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBryrNJGOLj-PSQirjnaRYC85BMq4_AzElPA0ZTcIJf8NNPrvPQ81TDx6juBLLo1ttM7Xd4Xvuhg73j-YAJJEmRZpA19SJcWjTMA0CQpVAFU64gIcq8hT5wx3bszgLa8QxSCWGxF45PEp6Altl8lDv_lG0YyesIhcbM3_z_9aHOHMdnVmr5sMmCzHZMU7w/s1600/Screenshot_14.jpg" width="267" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span> Hence block diagram of a.c. servomotor is</span><br /></span></p><p dir="ltr" style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO_sPhmMp1wmGN7S4QO589Bwfo6JHQznVRWi2ag-JjmRtOFnmdQSsQSf4rQnT_n3KEcECwoXMvILQaEWveYkvn0jRl4LVD43M-utLtBYlwEC7a2uD83YKRpn9YqU3FdDFtzRTSjJqzQrNRERXuGux_SKbgL11D1Y6vSnMOkD2gEH512CliLMZdvbJB7Q1e/s343/Screenshot_15.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="122" data-original-width="343" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO_sPhmMp1wmGN7S4QO589Bwfo6JHQznVRWi2ag-JjmRtOFnmdQSsQSf4rQnT_n3KEcECwoXMvILQaEWveYkvn0jRl4LVD43M-utLtBYlwEC7a2uD83YKRpn9YqU3FdDFtzRTSjJqzQrNRERXuGux_SKbgL11D1Y6vSnMOkD2gEH512CliLMZdvbJB7Q1e/s16000/Screenshot_15.jpg" /></span></a></div><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><b>Note</b>: As slope is negative, in the above equation [ B</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">m</sub><span style="font-size: large;">-m] shows that total friction increases due to m. As it adds more friction, the damping improves, improving stability of the motor. This is called internal electric damping of 2 ph a.c. servomotor.</span></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-75431133625370731022023-10-23T08:03:00.002-07:002023-10-23T08:03:57.872-07:00Transfer Function of Armature Controlled D.C. Motor<p> </p><span><a name='more'></a></span><p dir="ltr" style="text-align: left;"><b><u>Assumptions :</u></b></p><p dir="ltr" style="text-align: left;">i) Flux is directly proportional to current through field winding,</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbV5PHh4CpqLB9b_Xqf4oDS8SWxCoLXda7QspatigMzPXH_UyEd0nf8WARVg7Akm4kGc0nOiX91_UK2O3g1Ds4cavNWUG1MMQed9nwktEzwGEtzbdmq7IX6WoQhUB4rZNqRTceZtwgPtk3P56HRqZUA6p0u8w-suXclN7IsEv4XV3IkXorXL3ZQ0i7A9wS/s159/Screenshot_1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="32" data-original-width="159" height="32" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbV5PHh4CpqLB9b_Xqf4oDS8SWxCoLXda7QspatigMzPXH_UyEd0nf8WARVg7Akm4kGc0nOiX91_UK2O3g1Ds4cavNWUG1MMQed9nwktEzwGEtzbdmq7IX6WoQhUB4rZNqRTceZtwgPtk3P56HRqZUA6p0u8w-suXclN7IsEv4XV3IkXorXL3ZQ0i7A9wS/s1600/Screenshot_1.jpg" width="159" /></a></div><br /><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;">ii) Torque produced is proportional to product of flux and armature current</p><p dir="ltr" style="text-align: left;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIGzo6UgHRQW2lBvsi6kWVmCp0BSWOqA-z7DgP6-mpKAMosCCkVJAeCYu51v9xwK8BOdVxuk9P5NptfX8J15ckzNT9clXtkNYIZfeB-AUgXCqdxOmYQ9siPCgSd4RNEOhAkfIa6z_Ui6lak9MSdzLnx1VlrOLYbiZK0ttqIM2GmAkV3SrRxqgK6HH4ONnM/s124/Screenshot_2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="62" data-original-width="124" height="62" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIGzo6UgHRQW2lBvsi6kWVmCp0BSWOqA-z7DgP6-mpKAMosCCkVJAeCYu51v9xwK8BOdVxuk9P5NptfX8J15ckzNT9clXtkNYIZfeB-AUgXCqdxOmYQ9siPCgSd4RNEOhAkfIa6z_Ui6lak9MSdzLnx1VlrOLYbiZK0ttqIM2GmAkV3SrRxqgK6HH4ONnM/s1600/Screenshot_2.jpg" width="124" /></a></div><br />.<p></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;">iii) Back e.m.f is directly proportional to shaft velocity <span style="font-size: medium; text-align: justify;">ɸ</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">1</sub>, as flux ω is constant.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSj9lX5cCMN0JGzPEk2V7DW5SM8R_ZfoqcEU0PfA_UjXYyZxOm2lcX38hWodAe1k-uq5IZIXl9PDkxafLq322XGNsAnM1z06M4m8TG7rbkNkruGM64xrkANXSoK4A_IpIkdP2jsxZEHwysZAXYVAwOL1LaIXmoDQOHmqVALzVL8ZLz5BFe_ZxYyY9-O6ji/s434/Screenshot_3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="239" data-original-width="434" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSj9lX5cCMN0JGzPEk2V7DW5SM8R_ZfoqcEU0PfA_UjXYyZxOm2lcX38hWodAe1k-uq5IZIXl9PDkxafLq322XGNsAnM1z06M4m8TG7rbkNkruGM64xrkANXSoK4A_IpIkdP2jsxZEHwysZAXYVAwOL1LaIXmoDQOHmqVALzVL8ZLz5BFe_ZxYyY9-O6ji/s16000/Screenshot_3.jpg" /></a></div><br /><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"> Apply Kirchhoff's law to armature circuit :</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwGB0ybN_itYkGu2RdtPIcrj-a07_Wmx4hlqztJzt3oOZ4vNJmO8ePf31BUJxqMMxNx7u0qYU6H3ZRVculwUrJkDAAW1mdOExX-dmv6nor81xlvTu4JZi2DI8MGwtbFv7rUoeJJTqhvxOr4yhSEh89PtGMmThOeqNTnrMYI6vJKmWxxNIixERFv7INdTdQ/s183/Screenshot_4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="39" data-original-width="183" height="39" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwGB0ybN_itYkGu2RdtPIcrj-a07_Wmx4hlqztJzt3oOZ4vNJmO8ePf31BUJxqMMxNx7u0qYU6H3ZRVculwUrJkDAAW1mdOExX-dmv6nor81xlvTu4JZi2DI8MGwtbFv7rUoeJJTqhvxOr4yhSEh89PtGMmThOeqNTnrMYI6vJKmWxxNIixERFv7INdTdQ/s1600/Screenshot_4.jpg" width="183" /></a></div><br /><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"> Take Laplace transform</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXOW85fhFarD3eppXEhiWQHh1ZiiuZQerHlG7GzeZmqm0tlMfctce8jbNRkSbFv3u_sT_EUzcvrYdnaXQJCtdx7_XOwxTmdAfW_SLCPI5vQ2c7TIAh9nc4t9c018BVpfmFB4po1U97V2vgSNY8-nj5-l4fYYwhvcp5eefHy3ewG46p_ul2nF3ZOX2z9XJf/s528/Screenshot_5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="204" data-original-width="528" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXOW85fhFarD3eppXEhiWQHh1ZiiuZQerHlG7GzeZmqm0tlMfctce8jbNRkSbFv3u_sT_EUzcvrYdnaXQJCtdx7_XOwxTmdAfW_SLCPI5vQ2c7TIAh9nc4t9c018BVpfmFB4po1U97V2vgSNY8-nj5-l4fYYwhvcp5eefHy3ewG46p_ul2nF3ZOX2z9XJf/s16000/Screenshot_5.jpg" /></a></div><br /><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: justify;"> Equating equations of <span style="font-size: medium;">T</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">m</sub>,</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaR_0ItEX8ct0r3LANxFuSz5ndq19uZNHA47ASxo5phi3CW13lgFHR-iK4ieIdhyWdtK4p9gBmYs9GWKSHSSV40Zx-NCm3f39BsNUzWFHnKqW6IvWaHiAhnmNhGBz00J5ij3BVciujbrgLwVmaWw4MbVwUJfot_-g7a6xB6m-XoeGy2kf4LEXq2iCV7s8W/s545/Screenshot_6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="294" data-original-width="545" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiaR_0ItEX8ct0r3LANxFuSz5ndq19uZNHA47ASxo5phi3CW13lgFHR-iK4ieIdhyWdtK4p9gBmYs9GWKSHSSV40Zx-NCm3f39BsNUzWFHnKqW6IvWaHiAhnmNhGBz00J5ij3BVciujbrgLwVmaWw4MbVwUJfot_-g7a6xB6m-XoeGy2kf4LEXq2iCV7s8W/s16000/Screenshot_6.jpg" /></a></div><br /><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"> Therefore can be represented in its block diagram form as in<span style="color: #f3f3f3;"> </span><span style="color: #800180;">Fig.2</span>.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMQKQSAKU_MmvihxIMqjCQbz19ndWyJkMAlR3qEA04FuQ-A2Q5eD5tUMxPSTwh55L_1-6Sv2lHvXFZKj5hM6RLNWrE4SDzehO-Cwm42dVEuzK1pgLmlfwp1KGBJC1V0t4Gzk0awpLx7fYZNbamazUVso696xKbMQ6N7EgQOY1OGJJ5ImVAByT6cOzUBM3g/s370/Screenshot_7.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="122" data-original-width="370" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMQKQSAKU_MmvihxIMqjCQbz19ndWyJkMAlR3qEA04FuQ-A2Q5eD5tUMxPSTwh55L_1-6Sv2lHvXFZKj5hM6RLNWrE4SDzehO-Cwm42dVEuzK1pgLmlfwp1KGBJC1V0t4Gzk0awpLx7fYZNbamazUVso696xKbMQ6N7EgQOY1OGJJ5ImVAByT6cOzUBM3g/s16000/Screenshot_7.jpg" /></a></div><br /><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><br /></p><p dir="ltr" style="text-align: left;"><b>Note </b>: Field controlled d.c. motor is open loop while armature controlled is closed loop. Hence armature controlled d.c. motors are referred over field controlled type.</p><div style="text-align: left;"><br /></div><p><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-72891480062242771222023-10-22T04:20:00.006-07:002023-10-22T04:28:47.597-07:00Pascal’s Law<p><span style="font-size: medium;"> </span></p><span><span style="font-size: medium;"><a name='more'></a></span></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Blaise Pascal formulated this basic law in the mid-17th century. His law states that pressure in a confined fluid is transmitted undiminished in every direction and acts with equal force on equal areas and at right angles to container walls. Hydraulic brakes, lifts, presses, syringe pistons, etc. work on the principle of Pascal’s law.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> According to Pascal’s law, inside the pipes of a confined system pressure is uniform at all points. Mathematically,</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirrIUR1bALNB3heAHrC7VWxNxpHt46RcMND4Vs44zmDh90h2MTYjv3LQ18rx1xI0QhIo4ErZeFe63osRgiXAdWhCdh6kXb-kejjFxjrNVKxT8V14bioIRR0PHlo9p6SPcSxBsJb-7ENeYGnSpsTGm0MrrY64FpaUmZ5h6cALOoLaqVzyMprizmPPg5o49e/s571/Screenshot_10.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="303" data-original-width="571" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirrIUR1bALNB3heAHrC7VWxNxpHt46RcMND4Vs44zmDh90h2MTYjv3LQ18rx1xI0QhIo4ErZeFe63osRgiXAdWhCdh6kXb-kejjFxjrNVKxT8V14bioIRR0PHlo9p6SPcSxBsJb-7ENeYGnSpsTGm0MrrY64FpaUmZ5h6cALOoLaqVzyMprizmPPg5o49e/s16000/Screenshot_10.jpg" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJyWTD5H_jGtK_dTKYZGjPgKr7GjBE8UdtXPtClxWrg6LhupSXZcdY3x3QRJalfLP3gbSr_NyXsPhwghDCJXOY4qYfGVvuyij02aVk71MIvpTkY2qlrsnyiLCd99Nqt0z8_NzaCNgbeVDd_oMI8S1AI2O5fOXivN-Gb9C0sKEuz15CGUQba_ttnofCksDT/s200/Screenshot_11.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="119" data-original-width="200" height="119" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJyWTD5H_jGtK_dTKYZGjPgKr7GjBE8UdtXPtClxWrg6LhupSXZcdY3x3QRJalfLP3gbSr_NyXsPhwghDCJXOY4qYfGVvuyij02aVk71MIvpTkY2qlrsnyiLCd99Nqt0z8_NzaCNgbeVDd_oMI8S1AI2O5fOXivN-Gb9C0sKEuz15CGUQba_ttnofCksDT/s1600/Screenshot_11.jpg" width="200" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p style="text-align: justify;"><span style="font-size: medium;"> From the above expression, P</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">1</sub><span style="font-size: medium;"> = P</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">2</sub><span style="font-size: medium;">, therefore </span><span style="font-size: medium;">F</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">2</sub><span style="font-size: medium;"> is greater than </span><span style="font-size: medium;">F</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;"><span style="font-size: medium;">1</span><span style="font-size: small;"> </span></sub><span style="font-size: medium;">because </span><span style="font-size: medium;">A</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">2<span style="font-size: small;"> </span></sub><span style="font-size: medium;">is greater than </span><span style="font-size: medium;">A</span><sub style="font-family: Calibri, "sans-serif"; text-align: right;">1</sub><span style="font-size: medium;">. This means that, in order to obtain a greater output force, it is enough to have suitably sized surfaces available.</span></p><p style="text-align: justify;"><span style="font-size: medium;"></span></p><p style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><b><span style="color: #2b00fe; font-size: medium;"><u>Flow and Flow Rate</u></span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The volume of a substance passing a point per unit time is called flow and the volume of water, a pump or a compressor can move during a given amount of time is called, “flow rate.”</span></p><p dir="ltr" style="text-align: justify;"><span style="color: red; font-size: medium;">■<u> Volumetric Flow Rate</u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> It is the volume of the fluid flowing through a cross section per unit time. Air related flows are usually expressed in cubic feet per minute (CFM) and for liquid-based fluids, they are expressed as liters or gallons per minute (LPM or GPM) or cubic meters per second, etc.</span></p><p dir="ltr" style="text-align: center;"><span style="font-size: medium;"><b>Volumetric Flow Rate =Area × Velocity</b></span></p><p dir="ltr" style="text-align: left;"><span style="color: red; font-size: medium;"><span style="text-align: justify;">■</span><u> Mass Flow Rate</u></span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"> Volumetric flow rate times density, i.e., pounds per hour or kilograms per minute.</span></p><p dir="ltr" style="text-align: center;"><b><span style="font-size: medium;"><span>Ma</span><span>ss Flow Rate=Area × Velocity </span><span>×</span><span> Density</span></span></b></p><p style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFDf3iwo-v-_GYLCsO06DK-K8Kfz9h1OAPQj72WGnQp9OkNhsXPwAy32PtNmAiqltzlGWwFnqUOMNWXCFekgoJ_3QXj-zYe_0bdqxupCTlz9ays4PEEtkK0e5o4aIHnzUQXiABfgUMhMrREV6kqbB8l9HlSXdwjWhH-VYDdIKdqP1IYWWrYygDeaJqkwdu/s560/Screenshot_12.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="134" data-original-width="560" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFDf3iwo-v-_GYLCsO06DK-K8Kfz9h1OAPQj72WGnQp9OkNhsXPwAy32PtNmAiqltzlGWwFnqUOMNWXCFekgoJ_3QXj-zYe_0bdqxupCTlz9ays4PEEtkK0e5o4aIHnzUQXiABfgUMhMrREV6kqbB8l9HlSXdwjWhH-VYDdIKdqP1IYWWrYygDeaJqkwdu/s16000/Screenshot_12.jpg" /></a></div><br /><p style="text-align: justify;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-61579424258052553842023-10-22T03:54:00.003-07:002023-10-22T04:02:05.973-07:00Electrical Potential<p><span style="font-size: medium;"> </span></p><span><span style="font-size: medium;"><a name='more'></a></span></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> </span><span>In a water system, water can flow as long as pressure is applied to one end of a pipe and the other end of the pipe is open. The greater the pressure in a water system, the greater the quantity of water that will flow. Similarly, in an electrical system, electrons will flow as long as electric pressure is applied to the system. <span style="color: red;">Voltage, potential difference</span>, and <span style="color: red;">electromotive force </span>are all terms used to describe electric pressure.</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> </span><span>Recall that the law of electric charges states that unlike charges attract. Consequently, there is a pull, or force, of attraction between two dissimilarly charged objects. We call this pull of attraction a <span style="color: red;">field of force</span>.</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> </span><span>Another way of looking at this is to picture excess electrons (the negative charge) as straining to reach the point where there are not enough electrons (the positive charge). If the two charges are connected by a conductor, the excess electrons will flow to the point where there are not enough electrons. But if the two charges are separated by an insulator, which prevents the flow of electrons, the excess electrons cannot move. Hence, an excess of electrons will pile up at one end of the insulator, with a corresponding lack, or deficiency, of electrons at the other end.</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> </span><span>As long as the electrons cannot flow, the field of force between the two dissimilarly charged ends of the insulator increases. The resulting strain between the two ends is called the<span style="color: red;"> electric pressure</span>. This pressure can become quite great. After a certain limit is reached, the insulator can no longer hold back the excess electrons, as discussed in the previous section. Hence, the electrons will rush across the insulator to the other end.</span></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> </span><span>Electric pressure that causes electrons to flow is called voltage. Voltage is the difference in electric potential (or electric charge) between two points. The <span style="color: red;">volt </span>(V) is the amount of pressure required to force 1 <span style="color: red;">ampere </span>(A, the unit of measurement for current flow) through a resistance of 1 <span style="color: red;">ohm </span>(Ω, the unit of measurement for resistance; Ω is the Greek letter omega). In the industry, voltage is almost always measured in the range of the common volt. In other areas, the voltage may be measured on a smaller scale of a millivolt (mV), or one-thousandth of a volt. For larger measurements of the volt, the kilovolt (kV), equal to 1000 volts, is used.</span></span></p><p dir="ltr" style="text-align: center;"><span style="font-size: medium;">1 millivolt = 0.001 volt</span></p><p dir="ltr" style="text-align: center;"><span style="font-size: medium;">1 kilovolt = 1000 volts</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> To maintain electric pressure, we must have some way to move electrons in the same manner that water pressure moves water. In an electric circuit, this can be maintained by a battery, as shown in <span style="color: #800180;">Figure 1</span>, or by a generator or alternator, as shown in <span style="color: #800180;">Figure 2</span>. The battery forces electrons to flow to the positive electrode and causes electric pressure. A generator causes electric pressure by transferring electrons from one place to another.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWTWW0DiA0hMCtfaB2fYm4AXlIKrq6_y5bDK6kFPKL9nVeUwaoi9JVlYBy1ptcavcDf0I4JMbXMs8oD38ruoWB6PiPXDl01gqdrTv89Tc2CXgUqZd4GCtSaPfyX0-rhs5-19rLEX6wD48TGGoA_pbwYpzsdcX4Vo4on1IbEGf1-pxuAY4wI3IiDyVNDAbX/s517/Screenshot_9.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="266" data-original-width="517" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWTWW0DiA0hMCtfaB2fYm4AXlIKrq6_y5bDK6kFPKL9nVeUwaoi9JVlYBy1ptcavcDf0I4JMbXMs8oD38ruoWB6PiPXDl01gqdrTv89Tc2CXgUqZd4GCtSaPfyX0-rhs5-19rLEX6wD48TGGoA_pbwYpzsdcX4Vo4on1IbEGf1-pxuAY4wI3IiDyVNDAbX/s16000/Screenshot_9.jpg" /></span></a></div><span style="font-size: medium;"><br /><span><br /></span></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span> </span><span>Electromotive force can be produced in several ways. The most popular method of producing an electromotive force is by using an alternating current generator. The alternating current generator is supplied with power from another source. Then a wire loop is rotated through the magnetic field created by the voltage being applied, and an electromotive force is produced through the wire loop. We will discuss these ideas in more detail in succeeding sections.</span></span></p><p><span style="font-size: medium;"><br /></span></p><p><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-37596141886831238492023-10-22T03:42:00.002-07:002023-10-22T04:00:48.905-07:00Conductors and Insulators<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The structure of an atom of an element is what makes it different from the atom of another element. The number of protons, neutrons, and electrons and the arrangement of the electrons in their orbits vary from element to element. In some elements, the outer electrons rotating around the nucleus are easily removed from their orbits. As stated earlier, elements that have atoms with this characteristic are called conductors. A conductor can transmit electricity or electrons.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Most metals are conductors, but not all metals conduct electricity equally well. The most common conductors are silver, copper, and aluminum. The high cost of silver prevents it from being used widely. Its use is largely limited to contacts in certain electrical switching devices such as contactors and relays. Copper, almost as good a conductor as silver, is usually used because it is less expensive.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Materials that do not easily give up or take on electrons are called <span style="color: red;">insulators</span>. An insulator retards the flow of electrons. Glass, rubber, and asbestos are examples of insulators. Thermoplastic is one of the best insulators used to cover wire today. How well an insulator prevents electron flow depends on the strength of the potential applied. If the potential is strong enough, the insulator will break down, causing electrons to flow through it.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> There is no perfect insulator. All insulators will break down under certain conditions if the potential is high enough. Increasing the thickness of the insulation helps overcome this problem.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Conductors and insulators are important parts of electric circuits and electric systems. They are widely used in all electric components in the industry.</span></p><p style="text-align: justify;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-45933947330125070792023-10-22T03:35:00.001-07:002023-10-22T04:01:10.594-07:00Vehicle Closure Designs<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Apart from the vehicle doors, a vehicle body contains many openings that allow access to various parts of the vehicle. These include the following:</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Engine compartment hood</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Hatch and tailgate openings</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Fuel door</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><span>■ </span>Battery access cover (in some cases) or charging port door </span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A vehicle body contains many openings apart from the vehicle doors. these include the engine compartment hood, hatch and tailgate openings, the fuel door, and some cases a battery access cover. All of this openings have to be secured and may require a remote switch or lever to be activated. In some cases, the access door is opened mechanically by the driver pulling a lever, which moves a cable and release a latch. Other doors may use electric- or vacuum-operated solenoids to release the latch. In this case, the driver pushes a switch that sends electrical or vacuum signal to release mechanism, which release the door. Some rear hatch doors have a hinged window incorporated. This window offers easy access to the storage space without opening the entire back door.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixIir8wbHGJ0W8F9945P1a0i6BunD5pO07f4F1bHdrgx6elWgDCFfDYCUPy3xEchjm160QtMGYrQTS95hZ7Bwfrsql92SVaIL4gDXL0_ATpctjVbWr2qrQFiTDuRoH_rLdPRI6Ze9FxvaHg3PxE1CxKcNr0qF64WIZ0QHacRnvrWibjQs08BQhOUySyCZS/s385/Screenshot_7.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="321" data-original-width="385" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixIir8wbHGJ0W8F9945P1a0i6BunD5pO07f4F1bHdrgx6elWgDCFfDYCUPy3xEchjm160QtMGYrQTS95hZ7Bwfrsql92SVaIL4gDXL0_ATpctjVbWr2qrQFiTDuRoH_rLdPRI6Ze9FxvaHg3PxE1CxKcNr0qF64WIZ0QHacRnvrWibjQs08BQhOUySyCZS/s16000/Screenshot_7.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Engine compartment hoods on modern-day vehicles usually have a remote release lever. This lever prevents unauthorized access to the engine compartment. This is mainly for security reasons. The release lever is usually located inside the passenger compartment. It may be found under the dash, in the glove compartment, or on a doorjamb (<span style="color: #800180;">FIGURE 1</span>). Once the hood is open, it stays open by one of the following three methods: large springs on the hinges, pressurized gas strut assemblies, or a prop rod (<span style="color: #800180;">FIGURE 2</span>).</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3WIZbio011wWnuDHLRGCGpqUAxv9f0LgMz7iikybDYU-nSaLpQ-IRs2xOO8x5zERYrpQXOl3f88Wtj6TGAm6gFJEzWtuQeHXN8CM2czzq64Pg5F0ZYAleuf7ckQAWktgv3tMGneBXRrPg3NZAfNBjcfaBWeLw1igYs_U01oBiietPqE42kEFwKQwA9rZ6/s715/Screenshot_8.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="337" data-original-width="715" height="302" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3WIZbio011wWnuDHLRGCGpqUAxv9f0LgMz7iikybDYU-nSaLpQ-IRs2xOO8x5zERYrpQXOl3f88Wtj6TGAm6gFJEzWtuQeHXN8CM2czzq64Pg5F0ZYAleuf7ckQAWktgv3tMGneBXRrPg3NZAfNBjcfaBWeLw1igYs_U01oBiietPqE42kEFwKQwA9rZ6/w640-h302/Screenshot_8.jpg" width="640" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: left;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-90193726877092657422023-10-22T02:38:00.004-07:002023-10-22T04:01:31.529-07:00Vehicle Chassis<p><span style="font-size: medium;"> </span></p><span style="font-size: medium;"><a name='more'></a></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A <span style="color: #2b00fe;">chassis </span>is an underlying supporting structure where some vehicle components are mounted. It is similar to the skeleton of a human. In a vehicle, a traditional chassis gives the vehicle structural strength. It also has a platform to mount the engine, wheels, transmission, and all the other mechanical components. The vehicle body is also bolted onto this frame. Originally made of wood, vehicle chassis were soon changed to an open steel ladder-frame structure. This is easier to manufacture and is longer lasting (FIGURE 1).</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0xFr9bxgh82tVn36YYDx19mzG_CGKqg-3u6KWX7wTscrFK6E3jdRKqaqBMILp-3aZbY2WzoVOsu1uXqvEVlOr1Y-O2z7VP2XqXH2WHr2fIFZ1u18Q_wBB5ME0MygeeybqXT5zbywrLvOwWsstTLGnKENeiFmrETITUi1mF4w-UJhExHhnRzam07vyX0uM/s393/Screenshot_5.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="178" data-original-width="393" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0xFr9bxgh82tVn36YYDx19mzG_CGKqg-3u6KWX7wTscrFK6E3jdRKqaqBMILp-3aZbY2WzoVOsu1uXqvEVlOr1Y-O2z7VP2XqXH2WHr2fIFZ1u18Q_wBB5ME0MygeeybqXT5zbywrLvOwWsstTLGnKENeiFmrETITUi1mF4w-UJhExHhnRzam07vyX0uM/s16000/Screenshot_5.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Body-on-frame is the term used when a vehicle body is mounted on a rigid frame or chassis. It was the preferred way of building passenger vehicles. Manufacturers did not need to retool the structural components to release new models of vehicles with different body styles. However, by the 1960s, most manufacturers switched to vehicle designs that integrated the bodywork into a single unit with the chassis. The vehicle body became part of the vehicle structure rather than just an external skin. This is the unibody design, or single-shell design (FIGURE 2). The<span style="color: #2b00fe;"> unibody design</span> is constructed of many steel sheet metal panels. They are precisely formed in presses and spot-welded together into a structural unit.</span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIUUp3v8Rm1BP3BUeXTOpcRicRi8vvvb2wHaZXSzV8teuSir3b8onM20nXbk4VWsXiEt-O_YPI7-Kb5IYDLjttk3ZFnPRIdZJCZ1KfkbTKVY7C2jlqMdqg3sjngf7QaKq3o6UNtB__ah-pIlzN4Is_RJhwhfVmNMCx2vk1sbjMLRHJEFBQy-NVOq_OrhZb/s362/Screenshot_6.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="162" data-original-width="362" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIUUp3v8Rm1BP3BUeXTOpcRicRi8vvvb2wHaZXSzV8teuSir3b8onM20nXbk4VWsXiEt-O_YPI7-Kb5IYDLjttk3ZFnPRIdZJCZ1KfkbTKVY7C2jlqMdqg3sjngf7QaKq3o6UNtB__ah-pIlzN4Is_RJhwhfVmNMCx2vk1sbjMLRHJEFBQy-NVOq_OrhZb/s16000/Screenshot_6.jpg" /></span></a></div><span style="font-size: medium;"><br /></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The unibody design was first used in aircraft and then spread to automobiles. This is because with less of a chassis component, it was quicker to manufacture and lighter in weight. The lighter weight meant less cost in both material and labor. Another benefit of being lighter was that the vehicles became more fuel-efficient.</span></p><p><span style="font-size: medium;"><br /></span></p><p><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-43381298058988168312023-10-22T02:29:00.002-07:002023-10-22T02:38:43.560-07:00Overview of Vehicle Design<p><span style="font-size: medium;"> </span></p><span><span style="font-size: medium;"><a name='more'></a></span></span><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Vehicle bodies come in a variety of designs depending on the intended function of the vehicle. They are also designed to incorporate style, aesthetics, and, most importantly, safety. Vehicle body design has changed over time to accommodate the owners’ lifestyles and personal tastes (FIGURE 1). Look, for example, at the Scion XB or the Tesla Model X. Each of these vehicles has a unique body design to fit the needs and taste of its owner. Manufacturers also use vehicle body design in advertising to tempt buyers to purchase their vehicles.</span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> Common types of body design cater to both passenger and light commercial use. Terms to describe various body designs have become part of common automotive language. However, names describing the same body design type can vary from country to country. For example, a sedan in the United States is a saloon in the United Kingdom. This text will use U.S. terms. Types of body designs include the following:</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Sedan</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Coupe</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Hatchback</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Convertible</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Station wagon</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Pickup</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Minivan and van</span></p><p dir="ltr" style="text-align: left;"><span style="font-size: medium;"><span style="text-align: justify;">■ </span>Sport utility vehicle</span></p><p dir="ltr" style="text-align: left;"><b><span style="color: #2b00fe; font-size: medium;"><u>Sedan</u></span></b></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A sedan has an enclosed body, with a maximum of four doors to allow access to the passenger compartment (FIGURE 2). The sedan design also allows for storage of luggage or other items in a trunk. The trunk is located in the rear of the vehicle and is accessible from a trunk lid. A sedan traditionally has a fixed roof. However, there are soft-top versions of sedans, which have only two doors.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><b><u>Coupe</u></b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A coupe has only two doors. Reducing the number of passenger compartment doors makes the vehicle structurally more rigid. Traditionally, a coupe has two standard-size seats in front and possibly two smaller seats behind (FIGURE 3). Coupes are available in both a fixed roof and a convertible style. They also are equipped with a trunk for storage purposes. In most cases, the trunk is on the small side.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyi357Fq2KGOptB8yJPpPJCB5yfKONVd7Cccu54ODWPVyaxfGlUiJXyWGylUySa6tqA1z_2jNVswDcX1EtP6ocKqPZmItNGkHPCSUUJYxndj_dPvHxsiqUYxVLew2kGb_aI-hr4AoUkMyG9UJcnlWsfkW0UZWREUH9KYJ7-rwHpu6uTc3KppY90F9ati7F/s595/Screenshot_1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="449" data-original-width="595" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyi357Fq2KGOptB8yJPpPJCB5yfKONVd7Cccu54ODWPVyaxfGlUiJXyWGylUySa6tqA1z_2jNVswDcX1EtP6ocKqPZmItNGkHPCSUUJYxndj_dPvHxsiqUYxVLew2kGb_aI-hr4AoUkMyG9UJcnlWsfkW0UZWREUH9KYJ7-rwHpu6uTc3KppY90F9ati7F/s16000/Screenshot_1.jpg" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><u><b>Hatchback</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A hatchback is available in three-door and five-door designs. The odd-numbered door is a hatch that lifts up at the rear of the vehicle. This gives access to the luggage area. The rear seats usually fold down to increase the luggage area (FIGURE 4). Often, the rear seat is split. This allows one side to be folded down if the other seat is required for a passenger. Hatchbacks are versatile vehicles, combining some of the benefits of both sedans and station wagons.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><u><b>Convertible</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A convertible is an automobile with a roof that can be removed, retracted, or folded away (FIGURE 5). The roof is most often a flexible fabric such as canvas or vinyl. Most convertibles use electric motors that retract and raise the top. In some vehicles, known as hardtop convertibles, the roof is made of folding or fixed steel or fiberglass panels. When in place, the hard roof makes these vehicles look </span><span style="font-size: medium;">more like conventional fixed-roof coupe vehicles (FIGURE 6). In other vehicles, such as a T-top, only a smaller section of the roof area is convertible. The term roadster was applied to a vehicle with no permanent roof covering or side windows. Nowadays, the term is most often used to describe any convertible sports car.</span></p><p dir="ltr" style="text-align: left;"><span style="color: #2b00fe; font-size: medium;"><u><b>Station Wagon</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A station wagon has an extended roof that goes all the way to the rear of the vehicle. It is similar to a van but not as tall. The extra length in the roof increases the luggage capacity. In some cases, the passenger capacity is increased with extra seats in the very rear of the vehicle. Station wagons have a large rear door for easy access. The rear seats can usually be folded to increase the storage capacity even further (FIGURE 7). Station wagons usually have fixed roofs.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTJ26_qrUZugodu72_CLaSKmSPOeoqHDmDxotGn-VEpd2HB3wTym071ICj2H0FXq5x_yksnggC6xmEvAH7Z6WdYLQVycH9fiCCA4QjUzCbg59HgUcCw-VC-UQzVKYDjzTxoXlj-yemIuD5PEfvfmtrFDCymJi49Ktz4_A0QhyuE_idKxDBFbunJzr_39pR/s593/Screenshot_2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="472" data-original-width="593" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTJ26_qrUZugodu72_CLaSKmSPOeoqHDmDxotGn-VEpd2HB3wTym071ICj2H0FXq5x_yksnggC6xmEvAH7Z6WdYLQVycH9fiCCA4QjUzCbg59HgUcCw-VC-UQzVKYDjzTxoXlj-yemIuD5PEfvfmtrFDCymJi49Ktz4_A0QhyuE_idKxDBFbunJzr_39pR/s16000/Screenshot_2.jpg" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><u><b>Pickup</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The pickup, or truck, carries and tows cargo. Usually, it has heavier-duty chassis and suspension components than a passenger car. This is used to support greater loads. Traditionally, pickups had only a single cab with two doors. This limited the number of passengers they could carry. Today’s pickups have options for extended cabs or four-door versions to carry more passengers (FIGURE 8). In some cases, the four-door pickup has a reduced cargo-carrying space. This is to accommodate the extra seating in the cab.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><b><u>Minivan and Van</u></b></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> A minivan is usually a lighter-duty vehicle. Minivans have suspension systems similar to those in passenger cars. Alternatively, full-size vans use heavy-duty pickup truck– type suspension systems. Minivans can be configured in two different ways. The first way maximizes the number of seats for passengers. The second way maximizes the cargo space (FIGURE 9). Also, because they are light duty, the fuel economy of minivans is substantially better than that of full size vans.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibA-srbX1Vk9_5KCPg7Ze2whlBZhBbWaWC0zgVnkYTzi5E-nBpo_-T4oTGUqdrAj3gGtagld6FdFJwUPvl_vrle7UPMp9tg7OSj9eJSS5jBY78XBnlnrvGh9dsWiY0Tm54Qc2CmgYHfNux_wflQoQT2myl23pgE5LyKMEXlkiyHvOLQ0AVsceZhvD2Bev2/s454/Screenshot_3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="454" data-original-width="302" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibA-srbX1Vk9_5KCPg7Ze2whlBZhBbWaWC0zgVnkYTzi5E-nBpo_-T4oTGUqdrAj3gGtagld6FdFJwUPvl_vrle7UPMp9tg7OSj9eJSS5jBY78XBnlnrvGh9dsWiY0Tm54Qc2CmgYHfNux_wflQoQT2myl23pgE5LyKMEXlkiyHvOLQ0AVsceZhvD2Bev2/s16000/Screenshot_3.jpg" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="color: #2b00fe; font-size: medium;"><u><b>Sport Utility Vehicle</b></u></span></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"> The sport utility vehicle (SUV) is popular in the United States. SUVs can easily be used to carry out functions that would otherwise require several different vehicles (FIGURE 10). They act like both a full-size van and a pickup. They typically have a heavy-duty chassis so that they can carry heavier loads. This load can be in the form of passengers, luggage, or cargo. They can also tow moderately heavy loads. This makes them a great vehicle for family outings, as they can pull a trailer while still carrying a several passengers and luggage.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCyUEi7BMr8tlvZiTlq5jqgH4pW7QJ3yj9MnVpzDMfow85cL0YSBR18N_XSgUZjV0URcIDkTh4wx0q-1pAzO-in8NC2nSUnZLFQV0PLzU_9XupTBGmdvNyU7dAiGDFtQNHrHlLbrQFR2bl3zAG2MKYy55RTS3BW7YlKT1TJc7AtZ_EVD_cboYgJnh4UK0E/s294/Screenshot_4.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="233" data-original-width="294" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCyUEi7BMr8tlvZiTlq5jqgH4pW7QJ3yj9MnVpzDMfow85cL0YSBR18N_XSgUZjV0URcIDkTh4wx0q-1pAzO-in8NC2nSUnZLFQV0PLzU_9XupTBGmdvNyU7dAiGDFtQNHrHlLbrQFR2bl3zAG2MKYy55RTS3BW7YlKT1TJc7AtZ_EVD_cboYgJnh4UK0E/s16000/Screenshot_4.jpg" /></a></div><br /><span style="font-size: medium;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="font-size: medium;"><br /></span></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-2331856023661418782023-10-21T10:53:00.003-07:002023-10-21T10:53:56.233-07:00Overhead powerline hazards<p> </p><span><a name='more'></a></span><p dir="ltr" style="text-align: justify;"> Most people do not realize that overhead powerlines are usually not insulated. More than half of all electrocutions are caused by direct worker contact with energized powerlines. Powerline workers must be especially aware of the dangers of overhead lines. In the past, 80% of all lineman deaths were caused by contacting a live wire with a bare hand. Due to such incidents, all linemen now wear special rubber gloves that protect them up to 34,500 volts. Today, most electrocutions involving overhead powerlines are caused by failure to maintain proper work distances.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijJ9vIs95HZbyaqU3-AOfrnGK0k9tkgiyTNfnq2AiT-3J3FyhNxAXKaV_gde6ZvJXQ6URbgRwgML4HKfPE2ZdDdKex8AEX7coyeyXqKpr0qC1pEco7MhSHM6DYl51FXq3t-FBLaDjROkvWfuWr5YMCMEQOWAewF1OCUBnjJU2pw0CRIxMFQCUVp07P4zON/s564/Screenshot_15.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="564" data-original-width="291" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijJ9vIs95HZbyaqU3-AOfrnGK0k9tkgiyTNfnq2AiT-3J3FyhNxAXKaV_gde6ZvJXQ6URbgRwgML4HKfPE2ZdDdKex8AEX7coyeyXqKpr0qC1pEco7MhSHM6DYl51FXq3t-FBLaDjROkvWfuWr5YMCMEQOWAewF1OCUBnjJU2pw0CRIxMFQCUVp07P4zON/s16000/Screenshot_15.jpg" /></a></div><br /><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"><br /></p><p dir="ltr" style="text-align: justify;"> Shocks and electrocutions occur where physical barriers are not in place to prevent contact with the wires. When dump trucks, cranes, work platforms, or other conductive materials (such as pipes and ladders) contact overhead wires, the equipment operator or other workers can be killed. If you do not maintain required clearance distances from powerlines, you can be shocked and killed. (The minimum distance for voltages up to 50kV is 10 feet. For voltages over 50kV, the minimum distance is 10 feet plus 4 inches for every 10 kV over 50kV.) Never store materials and equipment under or near overhead powerlines.<span style="color: #800180;"> You need to recognize that overhead powerlines are a hazard.</span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicPz1R3dNm-Jq1UIdpfH2FQ-_ELSjqZ_JBxuwWrsjXs72Fm6_1r3-WWjHBG_MfjHCm80P0WcOhV5CgTM4U6c80GPF8mZkURSTE7dR_-wxFDjm5eig5nViQZwhblWNABGsvkoBEFtI3gYK7CeO8nHW_IT_llElQBZWud282xY0rgxhIPcjdQh818jKfmLdR/s336/Screenshot_16.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="290" data-original-width="336" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicPz1R3dNm-Jq1UIdpfH2FQ-_ELSjqZ_JBxuwWrsjXs72Fm6_1r3-WWjHBG_MfjHCm80P0WcOhV5CgTM4U6c80GPF8mZkURSTE7dR_-wxFDjm5eig5nViQZwhblWNABGsvkoBEFtI3gYK7CeO8nHW_IT_llElQBZWud282xY0rgxhIPcjdQh818jKfmLdR/s16000/Screenshot_16.jpg" /></a></div><br /><span style="color: #800180;"><br /></span><p></p><p dir="ltr" style="text-align: justify;"><span style="color: #800180;"><br /></span></p><p dir="ltr" style="text-align: justify;">Note:</p><p dir="ltr" style="text-align: justify;"><span style="color: #38761d;">■ Overhead powerlines kill many workers!</span></p><p style="text-align: justify;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0tag:blogger.com,1999:blog-5985378117830600098.post-91182270291448403702023-10-21T10:47:00.004-07:002023-10-21T10:56:05.632-07:00Exposed electrical parts hazards<p> </p><span><a name='more'></a></span><p dir="ltr" style="text-align: justify;"> Electrical hazards exist when wires or other electrical parts are exposed. Wires and parts can be exposed if a cover is removed from a wiring or breaker box. The overhead wires coming into a home may be exposed. Electrical terminals in motors, appliances, and electronic equipment may be exposed. Older equipment may have exposed electrical parts. If you contact exposed live electrical parts, you will be shocked. <span style="color: #800180;">You need to recognize that an exposed electrical component is a hazard.</span></p><p dir="ltr" style="text-align: justify;"><span style="color: #800180;"><br /></span></p><p dir="ltr" style="text-align: justify;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4MVGK9UwklRXFpYvWdGUeboF3Q24BPM9_5san8bshXM7Yzshgy0csJo8c1pLRsVm-ta20lUbINRZ9yhMFiQwLu7yfuEYAZwQueEncpa8-yqeEAQryu3ywM2qMUbXXY1T9w6fUey6R2ArX1Y9erkmBoIVngbyn343d4Avbz49D9ILnGK40_RySbjgl347l/s416/Screenshot_5.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="416" data-original-width="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4MVGK9UwklRXFpYvWdGUeboF3Q24BPM9_5san8bshXM7Yzshgy0csJo8c1pLRsVm-ta20lUbINRZ9yhMFiQwLu7yfuEYAZwQueEncpa8-yqeEAQryu3ywM2qMUbXXY1T9w6fUey6R2ArX1Y9erkmBoIVngbyn343d4Avbz49D9ILnGK40_RySbjgl347l/s16000/Screenshot_5.jpg" /></a></div><br /><span style="color: #800180;"><br /></span><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSQtkLKZMkvXV_2KeCGBVmbCGLE13q4SASfI8XNaTuvAWF9krwfLvtMP7oT8_xBbufeL5ydXDRb33X_jU3q1axBrJhjD90lEPzYSf-YgOR5pneftB4YsZQY_rqbKL4TtX35xPhWGp5ldH9eBRO6CzDyPHf2EHRHsI5LY9-UkaboFru-MHgaYTNs6NHdEJ8/s446/Screenshot_14.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="446" data-original-width="376" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSQtkLKZMkvXV_2KeCGBVmbCGLE13q4SASfI8XNaTuvAWF9krwfLvtMP7oT8_xBbufeL5ydXDRb33X_jU3q1axBrJhjD90lEPzYSf-YgOR5pneftB4YsZQY_rqbKL4TtX35xPhWGp5ldH9eBRO6CzDyPHf2EHRHsI5LY9-UkaboFru-MHgaYTNs6NHdEJ8/s16000/Screenshot_14.jpg" /></a></div><br /><p style="text-align: justify;"><br /></p>hamadahttp://www.blogger.com/profile/01954735072087881783noreply@blogger.com0