Explanation: Stray load losses cannot be determined accurately. In DC machine, by convention, it is taken as 1% of the rated output for rating above 150 KW. For synchronous and induction machine, it is taken as 0.5% of their rated output. 9. Which of the given losses are directly proportional to square of speed?
A. Windage loss
B. Eddy current loss
C. Both Windage and eddy current loss
D. Hysteresis loss and brush loss
Answer:A
Explanation: Stray load losses cannot be determined accurately. In DC machine, by convention, it is taken as 1% of the rated output for rating above 150 KW. For synchronous and induction machine, it is taken as 0.5% of their rated output. 9. Which of the given losses are directly proportional to square of speed?
A. Windage loss B. Eddy current loss C. Both Windage and eddy current loss D. Hysteresis loss and brush loss
Explanation: The windage loss includes the power required to circulate air through the machine and ventilating ducts, and is approximately proportional to the square of speed. Also, eddy current losses are proportional to square of speed. 10. Consider the following statements regarding efficiency of electrical machines: