Electrical Machines
Consider the following statements : For a level compounded dc generator to run at constant voltage, the series field mmf must effectively compensate 1. armature reaction mmf 2.armature resistance drop 3. brush contact voltage drop Which of these statements is/are correct ?

 1 and 3
 2 alone
 1, 2 and 3
 1 and 2

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Electrical Machines
A dc shunt generator, when commissioned after a major repair of the field system, failed to build Up voltage. It was because

 field system lost residual magnetism
 there was a break in the armature circuit
 field resistance was higher than critical resistance
 field winding was wrongly connected

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Electrical Machines
The results of a slip test for determining direct axis (Xd) and quadrature axis (Xq) reactances of a star connected salient pole alternator are given below Phase values: Vmax = 108 V ; Vmin = 96 V Imax = 12 A ; Imin = 10 A Hence the two reactances will be

 Xd = 9Ω and Xq = 9.6Ω
 Xd = 8Ω and Xq = 10.8Ω
 Xd = 10.8Ω and Xq = 8Ω
 Xd = 9.6Ω and Xq = 9Ω

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