3RT Series Ac Magnetic Contactor is suitable for use in the circuits up to the rated voltage 660V AC 50Hz or 60Hz, rated current up to 150A, for making, breaking, frequently starting & controlling the AC motor. Combined with the auxiliary contact block, timer delay & machine-interlocking device, etc, it becomes the delay contactor, mechanical interlocking contactor, star-delta starter. With the thermal relay, it is combined into the electromagnetic starter. The Contactor is produced according to IEC947-2, VDE0660 & BS5452.