How does an overload relay prevent motor damage?

An overload relay plays a critical role in protecting electric motors from damage caused by excessive current levels. When a motor experiences conditions that lead to increased load—such as jamming or mechanical failure—the current drawn by the motor rises. An overload relay monitors this current and is designed to trip, or shut off the motor, when it detects that the current exceeds a predetermined threshold. This tripping action interrupts the power supply to the motor, preventing overheating and potential damage to the motor windings and associated components.

The effectiveness of an overload relay lies in its ability to respond quickly to abnormal current conditions, thereby mitigating risks such as thermal overload, which can lead to motor failure if not addressed promptly. This protective mechanism is essential in ensuring the longevity and reliable operation of motors in various applications.