AC contactor usually adopts three arc extinguishing methods: double-break arc extinguishing, longitudinal slot arc extinguishing and grid arc extinguishing. AC contactor is used to eliminate the arc generated by the moving and static contacts during the opening and closing process. Contactors with a capacity of more than 10A have arc extinguishing devices. AC contactor also has auxiliary components such as reaction springs, buffer springs, contact pressure springs, transmission mechanisms, bases, and terminals.

The basic working principle of the AC contactor is to use the electromagnetic force to cooperate with the spring force to realize the connection and disconnection of the contacts. AC through the contactor has two management working and living states: de-energized state (release development state) and electrified state (action learning state). When the different coil systems are energized, the electromagnetic attraction force is generated between the static iron cores, the armature is pulled in, and the movement of the connecting rod connected to the armature drives the contact action, so that the normally closed contact breaking contactor control is in the energized state; When a power failure occurs in attracting these coils, the electromagnetic attraction gradually disappears, the armature is re-opened, the normally open contacts are closed, and the position springs are mainly released, and all the contacts are subsequently raised and reset, and the contactors are in a power-off state at the same time.