Not only can a synchronous motor drive a load with greater efficiency than an induction motor, a fringe benefit of the synchronous motor is the ability for power factor correction. What statement is true?

Correct Answer: Option C — If the overall plant has a unity power factor, the synchronous motor is normally-excited.

Under IEEE 45 standards, a normally-excited synchronous motor operates at unity power factor, neither supplying nor consuming reactive power. Over-excitation produces leading reactive power to correct lagging plant power factors, while under-excitation produces lagging reactive power. Thus, a unity power factor corresponds directly to normal rotor excitation.