The operating speed of a synchronous motor can be changed to new fixed value by___________?
Correct answer: C. changing frequency
- A. changing the load
- B. changing the supply voltage
- C. changing frequency
- D. using brakes
Explanation
Synchronous speed is given by Ns = 120f/P, so changing the supply frequency changes the motor's fixed operating speed. Changing load or voltage does not directly set a new synchronous speed.
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