The overload relay is a device used in electrical systems to protect electric motors from damage due to excessive current. It is typically connected to the motor circuit and detects the amount of current flowing through the motor. If the current exceeds a predetermined threshold, the overload relay trips and interrupts the power supply to the motor, preventing it from overheating or burning out.

In addition to thermal overload protection, some overload relays may also include other features such as phase loss protection, phase imbalance protection, and motor stalled protection. These additional functionalities further enhance the protection and monitoring capabilities of the motor.

Overall, the overload relay serves as a crucial component in ensuring the safe and reliable operation of electric motors, preventing damage and extending their lifespan.