Question

if field current is deceased in shunt DC motor, the speed of the motor. a) remains same
b) increase
c) decrease
d) none of the above ​

Answer 1

Answer:

decrease...

hope you understand

Answer 2

Explanation:

Intuitively we think that decreasing the field current should decrease the torque and motor should run slower. But exactly opposite happens. Because torque is dependent on both field current and armature current. When we reduce field current, Flux decreases and therefore according to (2), back emf (Eb) decreases.