In variable speed motor
A)a stronger commutating field is needed at low speed than at high speed
B)a weaker commutating field is needed at low speed than at high speed
C)same commutating field is needed at low speed than at high speed
D)none of the above is correct

Question

Quizplus · Accepted Answer

At low speeds, a weaker commutating field is required compared to high speeds because the induced current in the armature (which the commutating field must counteract to prevent sparking at the brushes) is lower due to the lower speed of rotation. At higher speeds, the induced current is higher, necessitating a stronger commutating field to effectively counteract it and ensure smooth operation.

In Variable Speed Motor