The relay is a device that uses low-current voltage and weak current circuit to control high-voltage and strong current circuit. Electromagnetic relay is a switch that uses an electromagnet to control the working circuit.
When the protected component of the power system fails, the relay protection device should be able to automatically, quickly and selectively remove the faulty component from the power system to ensure that the fault-free part quickly resumes normal operation and prevents the faulty component from continuing Suffered damage. Reduce the scope of power outages; by the early 1990s, the development, production, and application of integrated circuit and large-scale integrated circuit protection were in a dominant position, and the era of computer relay protection for intelligent information processing is currently being studied.
Application of electromagnetic relay
1. The electromagnetic relay is an important part of the electric bell, telephone and automatic control circuit device. Its essence is a switch controlled by an electromagnet, which plays a role similar to a switch in the circuit:
Use low voltage and weak current to control high voltage and strong current;
Realize remote control and automatic control.
2. The use of electromagnetic relays can use low voltage and weak current control circuits to control high voltage and strong current working circuits, and can realize remote control and production automation. Electromagnetic relays are widely used in automatic control (such as refrigerators, automobiles, elevators) , The control circuit in the machine tool) and the field of communication.