Red Seal Electrician Practice
Motor controlsQuestion 1272 of 1506

What is a problem of starting large motors directly on the line?

  1. The line voltage can sag and upset other loads.
  2. The motor can run backward whenever it is started on the line.
  3. The power factor can turn leading at start.
  4. The slip can become too low at start.
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Correct answer: The line voltage can sag and upset other loads.

The high starting current drops the voltage for loads on the same supply.

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

Practice motor controls

Questions last reviewed: 18 October 2026