In case-the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be______________?
Correct answer: D. less than 50%
- A. 100%
- B. around 90%
- C. anywhere between 75% and 90%
- D. less than 50%
Explanation
Maximum mechanical power occurs when the back e.m.f. is approximately half the supply voltage, making the developed power about half the input power before considering losses. Hence the actual motor efficiency is less than 50%.
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