Power factor and three-phaseQuestion 1014 of 1506

How are the voltages that are 120 degrees apart made in a three-phase alternator?

  1. A centre tap is placed on one of the windings
  2. Capacitors shift the phase of one of the windings
  3. Windings are spaced 120 degrees apart
  4. A resistor is placed in series with each phase winding
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Correct answer: Windings are spaced 120 degrees apart

The phase shift is built in by the winding position, so it does not depend on the load.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.2: Three-phase Power Systems

Practice power factor and three-phase

Questions last reviewed: 18 October 2026