Rotating Machines Flashcards
When rotor resistance is increased on an induction motor, what happens to the starting torque
The starting torque increases
A synchronous motor is used to correct a building’s power factor. Is the motor over or under-excited?
The synchronous motor is over-excited.
If rotor resistance is increased on an induction motor, what happens to the start up current?
The start up current will decrease
When rotor resistance is increased on an induction motor, what happens to the speed at full load?
The speed at full load decreases
When rotor resistance is increased on an induction motor, what happens to the efficiency?
The efficiency goes down (increasing rotor resistance increases real power losses which decreases efficiency)
When rotor resistance is increased on an induction motor, what happens to the power factor?
The power factor increases (there is a greater ratio of resistance to total impedance)
