Red Seal Industrial Mechanic (Millwright) Practice Exam

What does the term ‘service factor’ refer to in motor applications?

1. The voltage rating of the motor

2. The efficiency of the motor under load

3. The ability to handle loads beyond rated capacity

4. The temperature rating of the motor

The correct answer is: The ability to handle loads beyond rated capacity

The term ‘service factor’ in motor applications refers to the ability of a motor to handle loads that exceed its rated capacity under certain conditions. This factor provides a margin of safety for the motor, indicating how much additional load the motor can tolerate without overheating or sustaining damage over time. Service factors are typically expressed as a multiplier based on the motor's rated output. For example, a motor with a service factor of 1.15 can handle 15% more load than its rated capacity. This is particularly important in applications where load conditions can fluctuate or where there might be occasional overload situations. Understanding service factor is essential for ensuring reliable operation and longevity of the motor in various industrial applications, reinforcing the importance of not exceeding rated load limits without proper consideration of this factor.