In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made____________?
Correct answer: C. large in comparison with the armature mmf
- A. equal to that of armature mmf
- B. less in comparison with the armature mmf
- C. large in comparison with the armature mmf
- D. none of the above
Explanation
A strong field mmf dominates the armature mmf, so the armature reaction produces less relative distortion of the main field. This is why the field mmf is designed large in comparison with the armature mmf.
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