Question

In a single phase induction regulator, the voltage boost is maximum when armature mmf and rotor mmf make an angle of ____________

(a) zero degrees

(b) 45 degrees

(c) 90 degrees

(d) 180 degrees

The question was asked during an online interview.

This intriguing question comes from Machine Applications in division Electrical Machine Applications/Armature Reaction and Commutation of Electrical Machines

Answer 1

Right option is (a) zero degrees

For explanation I would say: To obtain a maximum of the voltage in induction regulator, the stator mmf and rotor mmf should be stationary and aligned to each other.