A dc shunt motor has external resistances of Ra and Rf in the armature and field circuits respectively. Armature current at starting can be reduced by keeping
A. Rf maximum and Ra minimum.
B. Ra maximum and Rf maximum.
C. Ra minimum and Rf maximum.
D. Ra maximum and Rf Minimum.
Answer:D
A dc shunt motor has external resistances of Ra and Rf in the armature and field circuits respectively. Armature current at starting can be reduced by keeping
A. Rf maximum and Ra minimum. B. Ra maximum and Rf maximum. C. Ra minimum and Rf maximum. D. Ra maximum and Rf Minimum.