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 gives more uniform air-gap flux distribution
 it reduces field structure iron losses

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
In a DC shunt generator working on load, the brushes are moved forward in the direction of rotation, as a result of this, commutation will

 improve but terminal voltage will fall.
  worsen and terminal voltage will fall
  worsen and terminal voltage will rise.
  improve and terminal voltage will rise .

ANSWER DOWNLOAD EXAMIANS APP