Power factor and three-phaseQuestion 1037 of 1506

One winding of a delta-connected three-phase source fails open. What is the effect on the load?

  1. The load loses all of its voltage and the neutral carries the load current
  2. The load voltage doubles on the two remaining phases
  3. The load voltage falls on only one phase and the others stay normal
  4. Load voltage and current are unchanged; other windings carry more
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Correct answer: Load voltage and current are unchanged; other windings carry more

The delta source is fault tolerant. The only effect is extra current in the remaining windings.

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