If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens
A)nothing will happen to th£ motor
B)this will make armature to take heavy current, possibly burning it
C)this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
D)motor will run at very slow speed

Question

Quizplus · Accepted Answer

When the shunt field circuit of a DC shunt motor opens while it is running, the field flux becomes very weak. Since the speed of a DC motor is inversely proportional to the field flux, a drastic reduction in field flux causes the motor to speed up excessively. This can lead to the motor reaching dangerously high speeds, potentially causing the armature to be destroyed due to excessive centrifugal forces.

If a DC Shunt Motor Is Working at No Load and If