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Can DC Contactor And AC Contactor Be Used Interchangeably?

May 15, 2018

DC CONTACTOR and AC CONTACTOR cannot be used interchangeably. Because when the AC contactor is connected to a DC power supply with the same rated voltage, constant current is unchanged, magnetic flux is also unchanged, the induced electromotive force is equal to zero, limiting factor for current only is resistance, so the DC current in the coil is much larger than the effective value of the AC current connected to the AC power supply and the coil will be burnt out. Conversely, if the DC contactor is connected to the AC power supply with the same voltage as the effective value, the coil will produce induced electromotive force. Limiting factors for the current factor in addition to the resistance, there is a lot of inductive reactance, so that the effective value of AC current is much smaller than the rated value, magnetomotive force and magnetic flow also reduced a lot, which make the contactor cannot be closed.