The 123-145 PM-B breaker is designed with interrupter, mechanism, and bushing technology and expertise that have been field proven on ABB SF6 dead tank breakers since 1992.
The 145PM-B breaker principally consists of three cast aluminum single-piece tanks, each containing an interrupter unit, mounted on a galvanized steel support structure. Two bushings with removable current transformers mount atop each tank. A steel control cabinet is attached to the frame, while the moving contacts are gang driven by a spring-hydraulic operating mechanism within the cabinet.
Reference : ABB (ABB/High Voltage Products/Circuit Breakers/Dead Tank Circuit Breakers)