USCG Exam PracticeMotors and generators
A synchronous motor is operating overexcited. What is the effect on the plant electrical system?
- A. The motor draws lagging reactive current, worsening the plant power factor
- ✓ The motor draws leading reactive current, correcting the lagging power factor of induction-motor loadsCorrect
- C. The motor speed increases above synchronous speed, causing instability
- D. The motor's damper windings become energized, reducing output torque
Why B is correct
NEETS Mod. 5 §4-2 states that by adjusting DC excitation to the overexcited condition, a synchronous motor draws leading reactive current, offsetting the lagging power factor of induction-motor loads. An overexcited synchronous motor used solely for this purpose is called a synchronous condenser.
Cited:NEETS Mod. 5 §4-2