What is the difference between an AC contactor and a DC contactor, and are they interchangeable?

The function of the contactor, functionally speaking, is used to isolate and cut off or pull in the electrical circuit. In essence, the AC and DC contactors are the same in terms of contacts, but the coil design is different, and the voltage used is different.
AC contactor is composed of electromagnetic system, contact system, arc extinguishing device and shell base.

AC contactors have the following characteristics:

①The iron core and the armature are made of silicon steel sheets;
②The AC voltage pull-in coil has a large impedance;
③A short-circuit ring is embedded in both the movable armature and the static armature;
④It has main contacts that are connected or disconnected and auxiliary contacts of varying numbers, and the main contacts are provided with arc extinguishing devices. as shown below

DC contactors have the following features:

①Its iron core and armature are made of solid material instead of silicon steel sheet;
②The DC voltage coil has a larger DC resistance value;
③ It has DC main contacts and auxiliary contacts of varying numbers. Some main contacts have arc extinguishing devices, and some do not have arc extinguishing devices. DC contactors are mainly used to connect and disconnect loads in DC circuits over a long distance.

DC contactor is also composed of electromagnetic mechanism, contact system and arc extinguishing device. For example, the electromagnetic mechanism is composed of an iron core, a pull-in coil and an armature, and mostly adopts a snap-fit ​​structure that rotates around edges and corners. Since the current passing through the pull-in coil is DC, under normal circumstances, eddy current will not be generated on the iron core when the coil is energized, so that the iron core does not generate heat, so it has no iron loss, so the iron core can be made of integral cast iron or cast steel . The number of turns of the DC low-voltage contactor coil winding is much more than that of the AC contactor coil, so the resistance value of the DC contactor coil is larger.
In addition, the working principle of the DC contactor is exactly the same as that of the AC contactor, so there is no need to say more here. To sum up the above, AC contactor and DC contactor cannot be used interchangeably. The above is my personal opinion, and I hope it will be helpful to the questioner.