A contactor is a device for opening and closing an electric power circuit.
Usually a magnetically operated switch for repeated operation, but may include a mechanical latching system to hold the contactor closed without requiring a continuous power supply.
A contactor differs from a circuit breaker in that it is able to operate a lot of times, >300000 compared to 10000 for a circuit breaker. Generally contactors have lower continuous current ratings than ANSI circuit breakers and have lower interrupting and making capacities.
A contactor is not intended to interrupt fault current on its own and is therefore often used in association with fuses or a circuit breaker.
Subjects: Electrical Engineering