Motor Overload Relay (MOR) is an essential component used in industrial electrical systems to protect electric motors from damage caused by overload conditions. Overload protection ensures the safety and longevity of motors, which are often critical components in various industrial applications. Without proper protection, motors are susceptible to overheating, reduced efficiency, and premature failure. In this article, we will explore the working principles, types, and applications of Motor Overload Relays, as well as their significance in the industrial world.

    The primary function of a Motor Overload Relay is to protect electric motors from being damaged due to prolonged overcurrent or overload conditions. The relay is designed to detect when the motor's current exceeds a preset threshold for an extended period. In such cases, the relay disconnects the power supply to the motor to prevent it from overheating, which could lead to insulation failure, reduced motor life, or even a complete motor burnout.

    The operation of the overload relay is typically based on the principle of thermal sensing. The relay is equipped with a heating element or a bimetallic strip that reacts to the temperature rise caused by excessive current flow. As the motor draws more current, the temperature inside the relay increases. Once the temperature exceeds the safe limit, the relay opens the circuit, cutting off power to the motor. This action provides vital protection to the motor, preventing it from reaching dangerously high temperatures.