Red Seal Electrician Practice
TransformersQuestion 1145 of 1506

A transformer under heavy load makes more noise. What is one cause?

  1. Repelling forces between the two windings
  2. A lower flux level in the core
  3. A short circuit inside the core
  4. Less current flowing in the secondary
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Correct answer: Repelling forces between the two windings

Load current creates opposing mmf in the windings. The result is a repulsive force that makes them vibrate.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.8: Practical Considerations - Transformers

Practice transformers

Questions last reviewed: 18 October 2026