What is the primary function of an overload relay?

The primary function of an overload relay is to protect the motor from excessive current. When a motor experiences an excessive load or malfunctions, it can draw more current than its rated capacity. This condition, known as an overload, can cause overheating, leading to potential damage to the motor windings and insulation.

The overload relay is designed to detect this increased current flow and respond accordingly by opening the circuit and disconnecting the motor from the power supply. This interruption protects the motor from overheating and prolongs its lifespan, ensuring reliable operation.

Understanding the role of the overload relay is crucial as it serves a specific protective function that is essential for maintaining motor health and safety in various applications. Other choices focus on aspects such as controlling speed, enhancing energy efficiency, or monitoring vibrations, but they do not capture the core protective characteristic of an overload relay, which is fundamentally aimed at safeguarding against excessive current conditions.