Electrical Machines Questions and Answers_pag155

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c) 
d) 
View Answer 
Answer: a 
Explanation: The power angle curve is not completely sinusoidal due to the salient nature of the 
poles. 
5. A 3 phase 400V salient pole alternator is running at no-load. Suddenly the excitation is 
removed then the net power in the machine is proportional to 
a) sin 2d 
b) sin d 
c) cos 2d 
d) 0 
View Answer 
Answer: a 
Explanation: The reluctance power generated will be proportional to sin(2δ). 
6. A 3 phase 400V cylindrical rotor is running at 1500rpm. Suddenly the field excitation zero. 
Then the net reluctance power is 
a) 0 
b) sin 2d