Red Seal Electrician Practice
TransformersQuestion 1043 of 1506

How is a three-phase transformer built?

  1. One primary winding that is wound around three separate cores
  2. Three sets of windings on one core, one set per leg
  3. Three separate cores that have no windings on them
  4. Two windings that are both wound on a single core leg
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Correct answer: Three sets of windings on one core, one set per leg

It is like three single-phase transformers that share a joined core.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.6: Three-phase Transformer Circuits

Practice transformers

Questions last reviewed: 18 October 2026