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The difference of contact system and electromagnetic system between dc contactor and ac contactor

Dec 27, 2018

The difference between dc contactor contact system and ac contactor contact system


The contactor of dc contactor also has the main and auxiliary parts. Unlike ac contactors, double breakpoint bridge contacts are usually used, due to the dc contactor main contact on and off the current is large, using the finger contact of rolling contact to extend the service life of the contact. However, the on-off current of auxiliary contacts is small, and double-breakpoint bridge contacts are often used.



The difference between dc contactor electromagnetic system and ac contactor electromagnetic system


The electromagnetic system of dc contactor is also composed of coil, core and armature. Armature and static core are patted together by armature rotating around edges and angles. Since the coil passes through direct current, the core is not heated by eddy current and hysteresis loss. Therefore, the core can be made of whole cast steel or cast iron, and the end face of the core does not need to be embedded with short circuit ring. In order to ensure the armature can be released reliably after the coil power off, non-magnetic gaskets are often used in the magnetic circuit to reduce the influence of remanence. Dc contactor coil turns more than ac contactor, large resistance, large copper loss, is the main component of heating in contactor. In order to make the coil radiate heat well, the coil is usually made into a long and thin cylindrical shape, and no skeleton is set, so that the coil and the core distance is very small, in order to use the core to send out some heat.