USCG Exam PracticeElectrical basics — generators, motors, and safety
Which type of AC motor runs at exactly synchronous speed and, when overexcited, can supply leading reactive power to improve plant power factor?
- A. Squirrel-cage induction motor
- B. Wound-rotor induction motor
- ✓ Synchronous motorCorrect
- D. Single-phase 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 induction motors run at slightly less than synchronous speed due to slip and do not inherently supply leading reactive power.