Which of the following are effects of armature reaction?(a) Increase in iron losses(b) Commutation problems(c) Possibility of commutator sparking(d) Increase in iron losses, commutation problems and commutator sparkingI have been asked this question in an interview.My question is based upon Armature Reaction topic in section Armature Reaction of DC Machines

Which of the following are effects of armature reaction?(a) Increase i

1.	Which of the following are effects of armature reaction?(a) Increase in iron losses(b) Commutation problems(c) Possibility of commutator sparking(d) Increase in iron losses, commutation problems and commutator sparkingI have been asked this question in an interview.My question is based upon Armature Reaction topic in section Armature Reaction of DC Machines
Answer» Right OPTION is (d) Increase in iron losses, commutation PROBLEMS and commutator sparking Explanation: Armature reaction in a DC machine is a result of distortion of MAIN field flux distribution by armature CURRENT, which produces its own mmf called armature mmf. Directly or indirectly armature reaction is the problem occurring in DC machine as it causes various effects, which reduce machine efficiency.

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