Red Seal Electrician Practice
TransformersQuestion 209 of 1506

A ferroresonant transformer is planned for a site that is powered by a small engine-driven generator with poor speed control. What is the problem?

  1. It cannot tolerate frequency changes
  2. The unit cannot be loaded at all
  3. The unit makes no heat on a generator
  4. It needs a DC supply to work
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Correct answer: It cannot tolerate frequency changes

A ferroresonant unit relies on a resonant circuit tuned to the line frequency, so it does not like a drifting frequency.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.6: Voltage Regulation

Practice transformers

Questions last reviewed: 18 October 2026