Red Seal Electrician Practice
Power factor and three-phaseQuestion 1041 of 1506

A delta-connected source has its three windings in a closed loop. Why does no large circulating current flow?

  1. The three voltages add up to zero around the loop
  2. The windings have very high resistance
  3. The neutral wire takes the circulating current
  4. The load blocks the circulating current
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Correct answer: The three voltages add up to zero around the loop

The phase angles make the vector sum zero, so there is no net voltage to drive a circulating current.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.5: Three-phase Y and Delta Configurations

Practice power factor and three-phase

Questions last reviewed: 18 October 2026