Red Seal Electrician Practice
TransformersQuestion 1092 of 1506

A step-up transformer is used backwards as a step-down transformer. What must the electrician check?

  1. The core must first be replaced with a solid iron core for the new duty.
  2. The supply frequency must be doubled to keep the flux the same.
  3. Each winding stays within its own design voltage and current.
  4. The two windings must be connected in series to share the load.
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Correct answer: Each winding stays within its own design voltage and current.

A winding is built for set voltage and current ranges. Outside those ranges the unit is inefficient or can be damaged.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.2: Step-up and Step-down Transformers

Practice transformers

Questions last reviewed: 18 October 2026