What is the primary function of a motor overload relay?

• A. To provide voltage regulation
• B. To open the motor circuit
• C. To increase motor speed
• D. To monitor temperature

Answer: (B)

The primary function of a motor overload relay is to open the motor circuit, protecting the motor from damage due to excessive current draw. When a motor operates beyond its rated capacity, it can overheat, which not only risks damaging the motor itself but can also lead to electrical fires or other hazards. The overload relay detects this condition and responds by interrupting the electrical circuit, effectively shutting down the motor to prevent further damage.

This protective mechanism is essential in industrial and commercial applications where motors are a critical component of machinery and operations. While voltage regulation and monitoring temperature are important aspects of motor control and safety, they do not directly encompass the primary function of overload protection. Increasing motor speed is not a function associated with an overload relay and does not contribute to the primary goal of safeguarding the motor's operational integrity.