Red Seal Electrician Practice
Motor controlsQuestion 1274 of 1506

What is the order of events in an autotransformer motor starter?

  1. Full voltage first, then reduced voltage after the start interval
  2. Reduced voltage for the whole life of the motor
  3. Reduced voltage first, then full line voltage after the start interval
  4. The autotransformer stays in series with the motor while it runs
Show answer

Correct answer: Reduced voltage first, then full line voltage after the start interval

The reduced voltage cuts the starting current, and the full voltage gives the normal running torque.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 13.7: Tesla Polyphase Induction Motors

Practice motor controls

Questions last reviewed: 18 October 2026