Red Seal Electrician Practice
MotorsQuestion 224 of 1506

Over what speed range is rotor resistance a useful speed control for a wound rotor motor?

  1. Only at exactly full speed
  2. About 0% to 50% of full speed
  3. About 100% to 200% of full speed
  4. About 50% to 100% of full speed
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Correct answer: About 50% to 100% of full speed

Added rotor resistance can lower the speed down to about half.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 13.8: Wound Rotor Induction Motors

Practice motors

Questions last reviewed: 18 October 2026