Basic parameters of AC contactor：

(1) Rated voltage: refers to the rated working voltage of the main contact, which should be equal to the rated voltage of the load.

(2) Rated current: the current value of the contactor contact under rated working conditions. In the 380V three-phase motor control circuit, the rated working current can be approximately equal to twice the control power. Common rated current levels are 5A, 10A, 20A, 40A, 60A, 100A, 150A, 250A, 400A, 600A. (3) on-off capacity: it can be divided into maximum on-off current and maximum on-off current. The maximum on-current refers to the maximum current value when the contact is closed without causing contact fusion welding; The maximum breaking current refers to the maximum current that can reliably extinguishment the arc when the contact is broken. The general on-off capacity is 5 to 10 times the rated current. Of course, this value is related to the voltage level of the breaking circuit, the higher the voltage, the smaller the on-off capacity.

(4) Action value: can be divided into suction voltage and release voltage. Priming voltage refers to the minimum voltage when the contactor can be priming by slowly increasing the voltage at both ends of the priming coil before the contactor is priming. The release voltage refers to the maximum voltage when the contactor is released and the voltage of the suction coil is slowly reduced after the contactor is pulled on. In general, the suction voltage is not less than 85% of the rated voltage of the coil, and the release voltage is not higher than 70% of the rated voltage of the coil

(5) Rated voltage of the suction coil: the voltage value added to the suction coil when the contactor is working normally.

(6) Operating frequency: The contactor in the suction moment, the suction coil needs to consume 5 to 7 times the rated current, if the operating frequency is too high, it will make the coil serious heat, directly affect the normal use of the contactor. Operating power is therefore required to limit it.

(7) Life: including electrical life and mechanical life. At present, the mechanical life of the contactor has reached more than 10 million times, and the electrical life is about 5% to 20% of the mechanical life.