Red Seal Electrician Practice
AC generationQuestion 1214 of 1506

Two alternators must be joined to one bus. What should be done before closing the switch?

  1. Run both at the same rate and bring their outputs in phase first.
  2. Run one alternator at double the speed of the other.
  3. Close the switch first, and then adjust the phase.
  4. Raise one output to a higher frequency so it takes the load.
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Correct answer: Run both at the same rate and bring their outputs in phase first.

The outputs must match in speed and phase, or they will pull against each other when joined.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 13.2: Synchronous Motors

Practice ac generation

Questions last reviewed: 18 October 2026