Red Seal Electrician Practice
Power factor and three-phaseQuestion 1063 of 1506

What happens to triplen harmonic currents in a delta-delta system?

  1. They flow in the lines at three times the size
  2. They circulate inside the delta loop
  3. They flow in the supply lines at double size
  4. They are converted into DC by the windings
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Correct answer: They circulate inside the delta loop

Because they are in phase, they act like a DC current around the delta loop.

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