USCG Exam PracticeMotor controllers and remote control
A three-phase squirrel-cage induction motor is started across the line. Compared to its full-load current, the starting inrush current is typically in which range?
- A. 1 to 2 times full-load current
- B. 3 to 4 times full-load current
- ✓ 5 to 7 times full-load currentCorrect
- D. 10 to 12 times full-load current
Why C is correct
NEETS Mod. 5 §4-1 states that induction motors draw a large starting inrush of five to seven times full-load current at a poor power factor because at standstill they behave like a short-circuited transformer. This is why reduced-voltage or soft starting is used on large motors.
Cited:NEETS Mod. 5 §4-1