A contactor is an electrically controlled switch used for switching an electrical power circuit.
Contactor comes in many forms with varying capacities and features, and combined with the auxiliary contact block, timer delay & machine- interlocking device etc, it becomes the delay co- ntact or, mechanical interlocking contact or, star- delta starter. With the thermal relay, it is combin- ed into the electromagnetic starter.
Contactors are used to control electric motors, lighting, heating, capacitor banks, thermal evapo- rators, and other electrical loads.