Red Seal Electrician Practice
AC generationQuestion 1015 of 1506

Why can a centre-tapped winding not produce three-phase voltages?

  1. A centre tap gives only 0 or 180 degree shifts
  2. A centre tap always shorts out the winding
  3. A centre tap makes the frequency three times too high
  4. A centre tap only works on DC circuits
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Correct answer: A centre tap gives only 0 or 180 degree shifts

Three-phase needs 120-degree shifts, which come from physically separate winding sets.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 7.2: Three-phase Power Systems

Practice ac generation

Questions last reviewed: 18 October 2026