Overload relays play a crucial role in the protection of electrical systems, especially when it comes to motors and other equipment. These devices are designed to prevent damage caused by excessive current, which can lead to overheating and even failure of electrical components. In this article, we will explore the working principle, types, applications, and importance of overload relays in modern electrical systems.

What is an Overload Relay? An overload relay is a protective device that is used to monitor the current in an electrical circuit, especially in motors. The primary function of an overload relay is to prevent motors from operating under excessive load conditions that could lead to overheating and failure. By detecting when the current exceeds a preset level, the relay triggers an action to disconnect the motor from the power supply, ensuring the safety and longevity of the equipment. Working Principle of an Overload Relay Overload relays operate based on the principle of detecting excess current in the system. There are two main types of overload relays： thermal overload relays and electronic overload relays.