Electrical Machines
In dc machine armature windings are placed on rotor because of the necessity for

 electromechanical energy conversion.
 development of torque.
 commutation.
 generation of voltage.

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

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

ANSWER DOWNLOAD EXAMIANS APP