What is the primary function of an overload relay?

The primary function of an overload relay is to protect motors from excessive current. This protective device is designed to monitor the current flowing through the motor. When the current exceeds a predetermined level, which typically indicates a potential overload condition, the relay will initiate a response to disconnect the power supply to the motor. This prevents overheating and potential damage to the motor, ensuring that it operates within its safe parameters.

Overload relays are essential in preventing damage from prolonged overload conditions, which can result from mechanical jams, increased load, or other factors. They are commonly used in conjunction with contactors or motor starters to provide comprehensive motor protection.

The other options relate to functions not associated with overload relays. For instance, enhancing electrical efficiency is more related to circuit design and power factor correction devices. Regulating voltage is typically the function of voltage regulators or transformers. As for initiating a circuit breaker reset, that is a function that pertains to circuit breakers rather than overload relays. Each of these operates under different principles and serves distinct purposes in electrical systems.