Electrical Machines
Dummy coils are used for

 increasing efficiency.
All of these
 mechanical balancing.
 reducing armature reaction.

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Interpoles in a DC motor must be

 Series excited and should have the same polarity as that of the behind main pole in the direction of rotation of armature.
 Shunt excited and should have the same polarity as that of the behind main pole in the direction of rotation of armature.
 Series excited and should have the same polarity as that of the ahead main pole in the direction of rotation of armature.
 Shunt excited and should have the same polarity as that of the ahead main pole in the direction of rotation of armature.

ANSWER DOWNLOAD EXAMIANS APP