Red Seal Electrician Practice
TransformersQuestion 1136 of 1506

A transformer built for 60 Hz is run at 50 Hz on the same voltage. What happens to the core flux?

  1. The peak flux is higher, so the core may saturate.
  2. The peak flux is lower, so the core is further from saturation.
  3. The flux is the same as it was at 60 Hz.
  4. The flux changes over to DC in the core.
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Correct answer: The peak flux is higher, so the core may saturate.

Each half-cycle lasts longer, so the flux climbs for longer and reaches a higher peak.

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

Practice transformers

Questions last reviewed: 18 October 2026