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, the back EMF of a motor is lower, which means the current through the armature is higher for a given voltage. This higher current can cause more significant magnetic interference, necessitating a weaker commutating field to properly counteract this effect and ensure efficient operation. At higher speeds, the back EMF is higher, reducing the armature current and thus requiring less compensation from the commutating field.

In Variable Speed Motor