Servo – Motor Automatic Voltage Stabilizer provides a continuous monitoring of the output voltage (true RMS sensing) by means of an electronic Control Circuit that compares the instantaneous output voltage with the set value. When changes are detected due to fluctuation of supply voltage or sudden changes in load, an electrical signal will be transmitted to the servo – motor which is coupled onto the brush gear of the variable transformer, causes the brush gear to rotate until the appropriate voltage is restored. This method of stabilization does not create interference or harmonic to the supply system. QPS Three phase Automatic Voltage Stabilizers also designed to cater for unbalanced load. This made possible with its independent phase monitoring system. They solve voltage unstable problems and increase productivity.