Series ac contactor is suitable for using in the circuits up to the rated voltage 660v ac 50hz, rated current up to 95a, 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 conactor, 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 & bd5452.