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

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
If the frequency of input voltage of a transformer is increased keeping the magnitude of voltage unchanged, then

 both hysteresis loss(Ph) and eddy current loss(Pe) will increase
 Pe will increase but Ph will decrease
 Ph will increase but Pe will decrease
 Ph will decrease but Pe will remain same

ANSWER DOWNLOAD EXAMIANS APP