Electrical Machines
When excitation is increased (over excitation), the synchronous generator operates at

 leading power factor.
 lagging power factor.
 any of the above.
 unity power factor.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
The introduction of interpoles in between the main poles improves the performance of a dc machine, because

 a counter-emf is induced in the coil undergoing commutation
 the interpoles produce additional flux to augment the developed torque
 the inequality of air-gap flux on the top and bottom halves of the armature is removed
 the flux waveform is improved with reduction in harmonics

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
A 3-φ alternator has negligible stator resistance. A short circuit test is conducted on this alternator. At a particular speed, a field current of If1 is required to drive the rated armature current. If the speed of the alternator is reduced to half, the field current required to maintain rated armature current

  Cannot be predicted due to insufficient data.
 Would be equal to If1.
 Would be equal to If1/2.
 Woud be equal to 2If1.

ANSWER DOWNLOAD EXAMIANS APP