In a synchronous motor running with fixed excitation, when the load is increased three times, its torque angle becomes approximately
Correct answer: C. thrice
- A. one-third
- B. twice
- C. thrice
- D. six times
- E. nine times
Explanation
For a synchronous motor, torque is proportional to sin of the torque angle. For the usual small-angle operating range, sin δ is approximately δ, so tripling the load approximately triples the torque angle.
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