Power factor and three-phaseQuestion 1019 of 1506

What is a polyphase power system?

  1. One that uses a single voltage waveform
  2. One that has only DC sources
  3. One that has two sources 180 degrees apart
  4. One with several sources at different phase angles
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Correct answer: One with several sources at different phase angles

Three-phase is the common example, with three voltages 120 degrees apart.

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