HOLT Electricians Practice Exam

Which of the following correctly describes the term "service factor" for motors?

1. A measure of energy efficiency

2. A multiplier of the motor's power output capacity

3. A specification for thermal protection

4. A factor influencing installation cost

The correct answer is: A multiplier of the motor's power output capacity

The term "service factor" for motors refers specifically to a multiplier of the motor's power output capacity. It indicates the extent to which a motor can be overloaded under specific operating conditions without causing damage or reducing its operational lifespan. For example, if a motor has a service factor of 1.5, it can safely operate at 150% of its rated horsepower for a limited time without risking overheating or failure. This measure is crucial for engineers and electricians when selecting motors for various applications where the load may fluctuate or exceed normal operating conditions temporarily. Understanding the service factor helps ensure that the motor is adequately sized for its intended application, contributing to both performance and durability. The other options relate to different attributes of motors but do not accurately capture the definition of service factor. Energy efficiency pertains to the ratio of output power to input power, thermal protection involves safeguards for overheating risks, and installation cost factors relate to the expenses associated with the motor's setup and integration into a system.