Due to the effect of armature reaction in DC machine, the flux per pole and generated voltage ______ and ________ respectively.(a) Increases, decreases(b) Decreases, decreases(c) Decreases, increases(d) Increases, increasesThe question was asked in final exam.This intriguing question originated from Armature Reaction -1 in section Armature Reaction of DC Machines

Due to the effect of armature reaction in DC machine, the flux per pol

1.	Due to the effect of armature reaction in DC machine, the flux per pole and generated voltage ______ and ________ respectively.(a) Increases, decreases(b) Decreases, decreases(c) Decreases, increases(d) Increases, increasesThe question was asked in final exam.This intriguing question originated from Armature Reaction -1 in section Armature Reaction of DC Machines
Answer» CORRECT option is (b) Decreases, decreases The explanation is: The nature of armature reaction in a dc machine is cross-magnetizing with its axis (stationary) along the q-axis (at 90° ELECT. to the main pole axis). It causes no change in flux/pole if the iron is unsaturated but causes REDUCTION in flux/pole (demagnetizing effect) in presence of iron SATURATION.

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