Electrical Machines
A dc shunt motor has external resistance Ra and Rf in the armature and field circuits respectively. Armature current at starting can be reduced by keeping

 Ra maximum and Rf minimum
 Ra maximum and Rf maximum
 Rf maximum and Ra minimum
 Ra minimum and Rf minimum

ANSWER DOWNLOAD EXAMIANS APP

Electrical Machines
Armature reaction in a DC machine

 makes an angle with the main pole axis which is load dependent.
  makes an angle of 90° with the main pole axis.
 is in direct opposition to the main poles.
 is in the same direction as the main poles.

ANSWER DOWNLOAD EXAMIANS APP