What is the marked service factor used in the 75-horsepower motor example?

What is the marked service factor used in the 75-horsepower motor example?

• A. 1.10
• B. 1.15
• C. 1.20
• D. 1.25

Answer: (B)

The marked service factor shows how much overload the motor can safely handle beyond its rated horsepower for short periods. It’s the multiplier printed on the nameplate used to calculate the maximum allowable output under service conditions. In the 75 HP motor example, the service factor given is 1.15. That means the motor can deliver up to 75 × 1.15 = 86.25 HP for brief periods, providing a 15% reserve above the labeled 75 HP. This is the intended overload capability for the example, which is why 1.15 is the correct marked service factor. The other values would correspond to different levels of overload allowance, but the example specifically uses 1.15.

The marked service factor shows how much overload the motor can safely handle beyond its rated horsepower for short periods. It’s the multiplier printed on the nameplate used to calculate the maximum allowable output under service conditions.

In the 75 HP motor example, the service factor given is 1.15. That means the motor can deliver up to 75 × 1.15 = 86.25 HP for brief periods, providing a 15% reserve above the labeled 75 HP. This is the intended overload capability for the example, which is why 1.15 is the correct marked service factor. The other values would correspond to different levels of overload allowance, but the example specifically uses 1.15.