MotorsQuestion 1028 of 1506

Why does a plain single-phase induction motor need help to start?

  1. Its rotor has no magnetic field at all
  2. It has no stator windings
  3. The supply voltage is too high for it
  4. Its field only alternates and has no rotation
Show answer

Correct answer: Its field only alternates and has no rotation

The motor can run either way once turning, but it cannot pick a direction by itself.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.4: Polyphase Motor Design

Practice motors

Questions last reviewed: 18 October 2026