What is the difference between electromagnetic relay and contactor
(1) The main function of the relay is for signal detection, transmission, conversion or processing. Its on-off circuit current is usually small, that is, it is generally used in the control circuit (compared with the "main circuit").

(2) The main function of the contactor is to connect or magnetic latching relay disconnect the main circuit. The so-called main circuit refers to whether a circuit works or not is marked by whether the circuit is connected. The main circuit concept corresponds to the control circuit. Generally, the current through the main circuit is larger than that of the control circuit. Therefore, as my friend on the first floor said, large-capacity contactors generally have an arc extinguishing cover (because a large current is disconnected, an arc will be generated, and if the arc extinguishing cover is not used, the contact will be burned out).

However, if the working current of a certain main circuit is relatively small, the electrical appliances usually used as relays can be used as devices for making and breaking the main circuit. The relay is used as a contactor. But if the working current of a certain main circuit is so large that the capacity of the contactor using the main circuit is very large, the current to make such a contactor work is also very large, that is to say, the current flowing in its control circuit is very large. Large, it is difficult to switch the control circuit with ordinary relays. At this time, you can choose an electrical appliance that was originally used as a contactor as the on-off of the control circuit. This contactor acts as a relay in this occasion.