The full-load armature current of a 440 𝑉 shunt motor is 120 𝐴. The armature resistance is 0.2 Ω and the speed is 800 rpm . If torque on the motor is reduced to 60 % of its full-load value and a resistor of 1.5 Ω is included in the armature circuit with field strength remaining same, the speed will be:
A. 700 rpm
B. 610 rpm
C. 520 rpm
D. 430 rpm
Answer:B
The full-load armature current of a 440 𝑉 shunt motor is 120 𝐴. The armature resistance is 0.2 Ω and the speed is 800 rpm . If torque on the motor is reduced to 60 % of its full-load value and a resistor of 1.5 Ω is included in the armature circuit with field strength remaining same, the speed will be:
A. 700 rpm B. 610 rpm C. 520 rpm D. 430 rpm