IBEW Electrical Practice Test 2026 – Complete Exam Preparation

A thermal overload relay is designed specifically to protect electric motors from damage due to overheating caused by excessive current. When a motor draws too much current, the thermal overload relay senses the increase in temperature and opens the circuit, thereby disconnecting the power and preventing potential damage to the motor windings.

This protective mechanism is crucial because overheating can lead to insulation failure and motor burnout, which are costly to repair or replace. The relay typically contains a bimetallic strip that bends in response to heat, triggering the opening of the circuit when a preset temperature is reached. The importance of a thermal overload relay in preventing overheating makes it an essential component in motor control circuitry.

Other options, while related to electrical components, do not accurately describe the function of a thermal overload relay. A switch for controlling power supply to a motor serves a different purpose, while a component that increases voltage refers to a transformer. Lastly, a fuse is designed to break a circuit when the current exceeds a certain level, but it does so in a different manner than a thermal overload relay, which specifically monitors heat rather than solely current flow.