A synchronous motor can operate at____________?
Correct answer: D. lagging, leading and unity power factors
- A. lagging power factor only
- B. leading power factor only
- C. unity power factor only
- D. lagging, leading and unity power factors
Explanation
Changing the field excitation changes the reactive current: under-excitation gives lagging power factor, correct excitation gives unity, and over-excitation gives leading power factor. Hence a synchronous motor can operate at all three.
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