The working principle of the ac contactor

Electromagnetic suction when energized coil,the static iron core,will be moving iron core and,as a result of the contact system is with the linkage of moving iron core,so core to drive three move contact run at the single phase electric motor same time,the contact closure,and connected to the power supply.Disappear when power coil,suction,moving iron core linkage part rely on spring reaction and separation,make the main contactor disconnect,cut off power supply.The choice of ac contactor:(1) the continuous operation of equipment.Contactor calculate by 67-75%.The 100 - a ac contactor,can control the maximum rated current is 67-75 - a the following equipment.(2) uninterrupted operation of equipment.Contactor calculate by 80%.The 100 - a ac contactor,can only control the maximum rated current is 80 a the following equipment.(3) and short- time working equipment.Contactor calculate by 116-120%.


The 100 a ac contactor,can only control the maximum rated current is below 116-120 - a device.Consider the work environment electric motors 12 volt and the structure of contactor.Also shows that:as the market competition is intense,to reduce the cost of domestic some manufacturer,has been in the corners,for example:in the coil production reduce wire diameter less number of turns around,even in touch head is not in conformity with the national standard of the material or thickness and the cross section is not ac electric motors enough.This kind of circumstance is not only reflected in the contactor,on top of other products such as short as well.Cause in be used actually,mark is 100 a contactor or short circuit,the actual load can only be even lower in 80 a,high failure rate.Popular theory is:so,now have to use domestic low-end products,to the rated capacity of 7 discount according to the www.facebook.com/dongfeng.motor nameplate instruction to use!