Red Seal Electrician Practice
AC generationQuestion 1205 of 1506

A clock with a synchronous motor on the AC line stays accurate for months. Why?

  1. A quartz crystal inside the motor corrects the line frequency drift each day.
  2. The rotor slips by a fixed amount that cancels any frequency change.
  3. The gear train adjusts itself whenever the line voltage changes.
  4. Operators make up any lost cycles, so the long-term line frequency stays correct.
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Correct answer: Operators make up any lost cycles, so the long-term line frequency stays correct.

A synchronous clock follows the line frequency, and operators correct the long-term cycle count.

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

Practice ac generation

Questions last reviewed: 18 October 2026