Question

How should the field mmf be with respect to armature mmf to reduce the armature reaction?

(a) armature mmf > field mmf

(b) armature mmf >= field mmf

(c) armature mmf < field mmf

(d) armature mmf = field mmf

The question was posed to me in an interview.

Enquiry is from Pole Design in division Thermal Design Aspects of Electrical Machines & D.C of Design of Electrical Machines

Answer 1

Correct answer is (c) armature mmf < field mmf

Explanation: To reduce the armature reaction, the field system should be designed such that the field mmf should be dominant over the armature mmf. If the armature mmf becomes low, the armature reaction reduces.