The relay control system is generally composed of main control devices, contactors, relays and wires. The logic function is completed by traditional relays. For example, the control time, there is a corresponding time relay, and the relay action is generally related to electromagnetic. . The relay can be considered as an electromagnetic switch. Applying a voltage to the coil creates a magnetic field that closes the contacts of the relay. Contacts are seen as switches, which allow current to flow, closing the main circuit.
The structure and working principle of the contactor are basically the same as those of the relay. The contactor also works by the principle of electromagnetic suction. The contactor system mainly includes a contact system, an electromagnetic system, an arc extinguishing device, a support base and a shell. It is used for the main circuit, large current, arc extinguishing device, generally can only operate under the action of voltage. Electromagnetic machines usually include three parts: the attraction coil, the iron core and the armature.