If excitation of a synchronous motor running with a constant load is decreased from its normal value, ignoring effects of armature reaction, it leads to
A)increase in both armature current and power factor angle
B)increase in back e.m.f. but decrease in armature current
C)increase in both armature current and power factor which is lagging
D)increase in torque angle but decrease in back e.m.f.

Question

Quizplus · Accepted Answer

Decreasing the excitation of a synchronous motor under constant load conditions results in a decrease in the back electromotive force (EMF). To maintain the power output, the armature current must increase. Additionally, the power factor angle increases as the motor operates with a more lagging power factor due to the reduced excitation.

If Excitation of a Synchronous Motor Running with a Constant