Red Seal Electrician Practice
MotorsQuestion 349 of 1506

What does the nameplate rpm of an induction motor represent?

  1. The synchronous speed of the rotating field
  2. The speed of the motor with the rotor locked
  3. The speed of the motor with no load at all
  4. The full-load rotor speed, a little below synchronous
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Correct answer: The full-load rotor speed, a little below synchronous

The rotor turns slower than the rotating field because of slip. The text calls the nameplate figure the slip speed, as opposed to synchronous speed.

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

Practice motors

Questions last reviewed: 18 October 2026