Electromagnetic relays and contactors work in the same way. Sometimes the same device is used in this circuit as a contactor and another circuit as a relay. How to distinguish? The way to distinguish is to see their specific uses.
The main function of a relay is to detect, transmit, transform or process signals. Its on-off circuit current is usually small, that is, it is generally used in the control circuit (compared with the "main circuit").
The main function of contactor is to connect or 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 or not. The concept of the main circuit corresponds to the control circuit. Generally, the current passed by the main circuit is larger than that of the control circuit. Therefore, as a friend on the first floor said, the contactor with large capacity is usually equipped with it. There is an arc extinguishing cover (because the arc will occur when the high current is disconnected, the contact will be burnt out if the arc extinguishing cover is not used).
If the working current of a main circuit is small, then it is possible to use the electrical apparatus usually used as relay to turn on and off the main circuit. That is to say, relay is used as contactor. But if the working current of a main circuit is so large that the contactor capacity of the main circuit is so large that such contactor can work. The current is also very large, that is to say, the current flowing through its control circuit is very large, and it is difficult to turn on and off its control circuit with ordinary relays. At this time, you can choose an electrical appliance used as a contactor to turn on and off the control circuit. The role of the contactor in this situation is the relay.
