HOLT Electricians Practice Exam

What is usually the result of incorrect overload protection device sizing on an electric motor?

1. Increased efficiency

2. Motor damage or failure

3. Improved safety

4. Lower energy consumption

The correct answer is: Motor damage or failure

The result of incorrect overload protection device sizing on an electric motor typically leads to motor damage or failure. Overload protection devices, such as circuit breakers or fuses, are designed to interrupt the current flow when it exceeds the motor's capacity. If the overload protection is sized too high, it may not trip when the motor experiences excessive current due to overload conditions. This can cause the motor to overheat, leading to insulation breakdown, overheating of windings, and eventual motor failure. Conversely, if the overload protection is sized too low, it may trip frequently during normal operation or minor overloads, causing unnecessary downtime and disruption. Therefore, accurate sizing is essential for safeguarding the motor, ensuring that it operates efficiently under expected load conditions while protecting it from potential damage. Properly sized overload protection enhances the lifespan of the motor by preventing conditions that lead to thermal and electrical stress.