Series Reactance Reduced Voltage
In this method, a voltage-dropping reactance is placed in series with the motor during starting. The impedance seen by the power system then is that of the reactance plus that of the motor.
START: R OPEN, S CLOSED
RUN: R CLOSED, S OPEN
CLOSED TRANSITION (R CLOSES BEFORE S OPENS)
Series Reactor Reduced Voltage Starting
- Motor terminal voltage is reduced from line voltage.
- Motor current equals line current.
- Starting torque is reduced by the square of the terminal voltage.
- Usually on high voltage and large low-voltage motors.
- Where current reduction requirements are low, or where load torque during acceleration is minimal.
- May be used for full acceleration or for system voltage recovery.