For general lighting purpose in shops, offices, houses, schools etc. Single phase a.c. supply is commonly used. Hence instead of d.c. motors, the motors which work on single phase a.c. supply are very popularly in use. These a.c. motors are called single phase induction motors. The numerous domestic applications use single phase motors. The power rating of such motors is very small. Some of them are even fractional horse power motors, which are used in applications like small toys, small fans, hair dryers etc. This chapter explains the construction, working principle and applications of various types of single phase induction motors.
Similar to a d.c. motor, single phase induction motor has basically two main parts.one rotating and other stationary. The stationary part in single phase induction motors is called stator while the rotating part is called rotor.
The stator has laminated construction, made up of stampings. The stampings are slotted on its periphery to carry the winding called stator winding or main winding. This is excited by a single phase a.c. supply. The laminated construction keeps iron losses to minimum. The stampings are made up of material like silicon steel which minimises the hysteresis loss. The stator winding is wound for certain definite number of poles means when excited by single phase a.c. supply, stator produces the magnetic field which creates the effect of certain definite number of poles. The number of poles for which stator winding is wound, decides the synchronous speed of the motor. The synchronous speed is denoted as Ns and it has a fixed relation with supply frequency f and number of poles P. The relation is given by,
The induction motor never rotates with the synchronous speed but rotates at a speed which is slightly less than the synchronous speed.
The rotor construction is of squirrel cage type. In this type, rotor consists of uninsulated copper or aluminium bars, placed in the slots. The bars are permanently shorted at both the ends with the help of conducting rings called end rings. The entire structure looks like cage hence called squirrel cage rotor. The construction and symbol is shown in the Fig..1
 |
| Fig. 1 |
As the bars are permanently shorted to each other, the resistance of the entire rotor is very very small. The air gap between stator and rotor is kept uniform and as small as possible. The main feature of this rotor is that it automatically adjusts itself for same number of poles as that of the stator winding.
The schematic representation of two pole single phase induction motor is shown in the Fig.2. 
Sponsored links :
it is a very good post i like well. it is a neat and straight point of explanation
ReplyDeletealternator
nice explanation
ReplyDeleteVery use full for studies... I like it. Straight to point and reader friendly. Helps a lits to clear all concepts. Thank you. Keep going.
ReplyDeleteHow no of poles is constructed by winding
ReplyDeleteThat is what to do for changes no of poles
can i get all your blog in pdf format..the stuffs here are really good and i need them. please mail to me at barath27kumar@gmail.com
ReplyDeletegood explanation
ReplyDeletehttp://www.top-ee.com/working-principle-of-single-phase-induction-motor/
Furthermore, with an exhaustive variety of rugs being offered in the virtual market, no matter whether you need to buy a shag rug or a vintage rug, you are sure to find suitable discount rugs in no mentionable time.visit this site
ReplyDeleteIs a safety sweep
ReplyDeleteOne thing you don't want your children to become aware of over the first few days of this step is the first aid kit. Your children will want to explore this, before you let them flee the leash, wandering around in your new home like a safety inspector. شركة نقل اثاث
شركة نقل عفش بالخرج
The adjacent thing you can do is focus upon tracking casio pro trek smart wsd-f30 your bet results. It may be recorded on paper or collected using a mobile phone to write next to your betting records statistics and enter actual information. Enter each bet honestly upon yourself, win, win, lose and lose. Sometimes, you may not be adept to direct the health of your betting account. Beware of your budget. And compare it bearing in mind betting statistics to find a habit to give the best account health.
ReplyDelete