In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except______________?
Correct answer: B. dummy coils
- A. interpoles
- B. dummy coils
- C. compensating winding
- D. shifting of axis of brushes
Explanation
Interpoles, compensating windings, and suitable brush shifting help neutralize the reactance emf during commutation. Dummy coils are not electrically connected and cannot reduce commutation sparking.
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