Electrical Machines
In dc machines, the field system has to be provided on stator unlike synchronous machines Where in it could be on any member, because

 commutator action is not possible otherwise
 dc machines are comparatively low rating machines.
 it reduces field structure iron losses
 it gives more uniform air-gap flux distribution

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
In DC machines, the interpoles are provided

  both (B) and (C).
  to make commutation spark less.
 to counteract demagnetizing effect of armature mmf in commutating zone.
 to counteract the reactance voltage and the cross-magnetizi

ANSWER DOWNLOAD EXAMIANS APP