Operating principle of ac contactor:

When the AC contactor coil is connected with the electric source, coil generates a magnetic field, as there is an electic current.The static iron of ac contactor core under the action of electromagnetic force, to overcome the spring reaction force, with the moving core pull, so that the dynamic and static contacts, and then main circuit is switched on; and when the ac contactorcoil is out of power, static iron core of the electromagnetic suction die, core in the spring reaction force reduction, so that the movable contact and the static contact detachment, cut off the main circuit.