Three Phase Air Cooled Servo Voltage Stabilizer is designed to give a constant output voltage for single as well as three phases applications with stability ±% of the efficiency has been maintained a high as 98% or more. The Stabilizer has control card for efficient operation on mains as well as DG set. The Stabilizer has the feature that output voltage stability allows the good drawing of the current by load and as such no extra electrical power is consumed at low as well as high voltage. The Stabilizer has microprocessor. The Three Phase Air Cooled Servo Voltage Stabilizer has operating temperature ranging from 15 ° C to 50° C, number of load loss less than 1% and has auto or manual operation.