An overload relay is a protective device that detects excessive current in an electrical circuit, which can occur due to various reasons, such as motor failure, system malfunctions, or overload conditions. When the current exceeds the preset threshold, the overload relay disconnects the circuit to prevent damage to the electrical equipment. The main purpose of the overload relay is to safeguard devices, particularly motors, from thermal and mechanical stress that can occur under abnormal current conditions.

    How Does an Overload Relay Work?

    Overload relays operate by monitoring the current flowing through an electrical circuit. They are often connected in series with the motor or the equipment they protect. The relay typically contains a thermal element that responds to the heat generated by excessive current. When the current is higher than the normal operating range, the thermal element heats up, and once it reaches a specific temperature, the relay opens the circuit, thus interrupting the flow of electricity.