Power factor and three-phaseQuestion 1057 of 1506

What are triplen harmonics?

  1. All harmonics above the 10th
  2. Harmonics that exist only in single-phase systems
  3. The 3rd harmonic and its integer multiples
  4. Harmonics that cancel in the neutral
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Correct answer: The 3rd harmonic and its integer multiples

The 3rd, 6th, 9th and so on are in phase in all three phases of a three-phase system.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.7: Harmonics in Polyphase Power Systems

Practice power factor and three-phase

Questions last reviewed: 18 October 2026