Red Seal Electrician Practice
MotorsQuestion 186 of 1506

A motor nameplate shows no service factor. What does this mean?

  1. The motor can never be overloaded for any length of time
  2. The motor must be derated by ten percent of its rating
  3. The service factor is no higher than one
  4. The motor needs no overload protection device at all
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Correct answer: The service factor is no higher than one

The nameplate lists a service factor only when it is higher than one, so a missing value means one or less.

Source: Troubleshooting Motors and Controls (Dickson-Self), 6.1: Testing Motor Components

Practice motors

Questions last reviewed: 18 October 2026