USCG Exam PracticeElectrical fundamentals — DC/AC, motors, distribution
Which type of AC motor requires a separate DC excitation source for its rotor and can supply leading reactive power to correct plant power factor when overexcited?
- A. Squirrel-cage induction motor
- B. Wound-rotor induction motor
- ✓ Synchronous motorCorrect
- D. Compound-wound induction motor
Why C is correct
DOE-HDBK-1011 Vol.4 §12-1 states that the synchronous motor runs at exactly synchronous speed with a DC-excited rotor and, when overexcited, supplies leading reactive power to correct plant power factor. Squirrel-cage and wound-rotor motors are induction types that operate with slip and do not require rotor excitation.