A synchronous motor connected to infinite bus-bars has at constant full load, 100% excitation and unity power factor. On changing the excitation only, the armature current will have
A)no change of power factor
B)lagging power factor with over-excitation
C)leading power factor with under-excitation
D)leading power factor with over-excitation

Question

Quizplus · Accepted Answer

When the excitation of a synchronous motor is increased beyond the level required for unity power factor, it becomes over-excited, causing the motor to operate at a leading power factor.

A Synchronous Motor Connected to Infinite Bus-Bars Has at Constant