- core is not the same: AC contactor has a core made of silicon layers insulated from each other, and made double E-shaped; multi-core DC contactor from a single piece of soft iron, mostly U-shaped;
- the interrupter system is not the same: the use of AC contactor interrupter delete sheet, and DC contactors using magnetic blow interrupter device.
- the number of turns is not the same: AC contactor coil turns less pass into the alternating current, and DC contactor coil turns into the multi-way DC, AC contactor breaking the AC circuit, breaking the DC contactor DC circuit. AC contactor operating frequency up to 600 cycles / hour,
The use of low cost, while the DC contactor operating at frequencies up to 2000 times / hour, the use of high cost.
Why are not interchangeable:
1, AC contactor in an emergency can substitute DC contactors, time can not pull more than two hours (because of the heat exchange coil worse than DC, which is structurally different by their decision), really want to use the best in a long time AC coil in series a resistor, in turn, can not substitute AC DC contactor
Under 2, AC contactor coil turns less, the DC contactor coil turns more, from the size of the coil can be distinguished for the main circuit current is too large (Ie> 250A) of the case, the contact adopts double winding in series DC relay coil electric coil Kang Da, current. If connected to AC power is not loss, when timely release. But AC electrical relay coil resistance is small, the current big, will be damaged if connected to a DC coil.
4, AC contactor coil turns less, resistance is small, when alternating current through the coil, it will generate a large inductance, reactance this is far greater than the resistance of the coil, the coil excitation current depends on the inductance the size of. If introduced into the DC, the coil becomes purely resistive load, the current flowing through the coil at this time will be large, so that the coil heat, even burn. Therefore, it can not be used as an AC contactor DC contactor.