An AC contactor is an automatic switching electrical device that connects or disconnects the main circuit of an electric motor or load. It is an electrical appliance that uses electromagnetic force to close or open the switch, suitable for frequent operation, long-distance control of strong electrical circuits, and has protection performance of low-voltage release. It is used for long-term and high-frequency switching of AC main circuits and control circuits, and has the advantages of automatic operation, voltage loss and under-voltage protection, large capacity operation, strong stability, and low maintenance requirements. [2]
The contactors usually adopt three arc-extinguishing methods: double-break arc-extinguishing, longitudinal seam arc-extinguishing and grid plate arc-extinguishing. These methods are used to eliminate the arcs generated during the opening and closing of the moving and static contacts. Contactors with a capacity of 10A or above all have arc-extinguishing devices. The contactors also have auxiliary components such as counteracting springs, buffer springs, contact pressure springs, transmission mechanisms, bases and terminal posts. [1]