Views: 2 Author: Site Editor Publish Time: 2022-12-14 Origin: Site
Although AC contactors and DC contactors have similar functions, they cannot be mixed, otherwise they will not work properly.
The AC contactor is an automatic switch powered by AC power. There is an "instantaneous zero crossing" process when the alternating current turns from a positive half cycle to a negative half cycle. At the moment of "zero crossing", the voltage and current are "zero". The electromagnet coil will "lose attraction" at this time. Therefore, the electromagnet using alternating current has a short-circuit ring on the pole surface of the armature , the accurate name is "phase-shifting loop". The function is to make the current of the alternating current lag behind the electric angle of the voltage (so that it does not cross zero at the same time). It can avoid that the voltage and current cross zero at the same time, and the electromagnet loses its attraction instantaneously status of power.
In actual use, if a ac contactor switch using a DC power supply, or other iron-core electromagnetic coils, is connected to an AC circuit, even if there is no difference in the nominal voltage, there will be a huge noise and vibration, and the current will increase greatly. The coil will heat up rapidly and burn out. Assuming that the driving coils of these two general contactors are both AC or DC, and the voltage level is the same, the main difference between them is that the structure of the arc extinguishing device of the main contact is different, and there is a magnetic blowing coil under the main contact of the DC contactor , the AC contactor for ac does not.