A 220 𝑉 shunt motor has an armature resistance of 0.5 Ω and takes armature current of 40 𝐴 at full load. To raise the speed by 50 % if developed torque is constant, the main flux to be reduced will be:
A. 49.0 %
B. 45.0 %
C. 41.5 %
D. 37.5 %
Answer:D
A 220 𝑉 shunt motor has an armature resistance of 0.5 Ω and takes armature current of 40 𝐴 at full load. To raise the speed by 50 % if developed torque is constant, the main flux to be reduced will be:
A. 49.0 % B. 45.0 % C. 41.5 % D. 37.5 %