Red Seal Electrician Practice
TransformersQuestion 1114 of 1506

Why is an AC arc welder transformer built with poor voltage regulation?

  1. It keeps the welding current constant even at no load.
  2. It limits the harmonics that the welder puts on the supply.
  3. It stops the core from saturating when the arc is struck.
  4. A high open-circuit voltage strikes the arc, then it falls.
Show answer

Correct answer: A high open-circuit voltage strikes the arc, then it falls.

A high voltage helps start the arc. Once the arc is on, less voltage is needed, so a voltage drop under load is helpful.

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

Practice transformers

Questions last reviewed: 18 October 2026