Contactor is a kind of automatic electromagnetic switch, which is suitable for making breaking AC / DC main circuit large capacity control circuit frequently in long distance. Its main control object is motor, can also be used to control other loads. It can only realize remote automatic operation undervoltage release protection, but also has the advantages of large control capacity, reliable operation, high operation frequency long service life, so it has been widely used in electric drive system. The contactor is divided into AC contactor DC contactor according to the current type of main contact.

DC contactor is mainly used for making breaking DC circuit at a long distance, starting, stopping, reversing reverse connecting brake DC motor frequently, also used for frequently connecting disconnecting lifting electromagnet, solenoid valve, clutch solenoid coil, etc. DC contactor has two kinds of structure: three-dimensional layout plane layout. Some products are derived AC contactor. Therefore, the structure working principle of DC contactor AC contactor are basically the same, mainly composed of electromagnetic mechanism, contact system arc extinguishing device. Because DC arc does have natural zero crossing point like AC arc, it is more difficult to extinguish arc when main contact of DC contactor breaks large current (DC circuit), which often produces strong arc, which is easy to burn contact delay power-off. In order to extinguish the arc rapidly, in order to extinguish the arc rapidly, the DC contactor generally adopts the magnetic DC contactor, generally adopts the magnetic DC contactor, generally adopts the magnetic direct current contactor, generally adopts the magnetic blowing type arc extinguishing device, the blowing type arc extinguishing device is equipped with the partition board the ceramic arc extinguishing cover, is equipped with the partition board the ceramic arc extinguishing cover The plate the earthenware arc extinguishing cover are equipped with partition board earthenware arc extinguishing cover.