In variable speed motor___________?
Correct answer: B. a weaker commutating field is needed at low speed than at high speed
- 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
Explanation
At higher speed, commutation occurs in less time, so a stronger interpole or commutating field is needed to reverse armature current properly. Therefore the required commutating field is weaker at low speed than at high speed.
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