Voltage fluctuation has adverse effects on the performance as well as the life of any electrical machine, instrument, equipment or tool. Each type of the machine has different voltage requirement. In order to maintain the voltage supply to the appliance or industrial equipment or medical devices, one must install a stabilizer. Servo stabilizer have proven its effectiveness and efficiency for years. There are many models available and one is Oil Cooled Three Phase Variac Type Servo Stabilizer, which is capable of working on both, extremely low as well as high load efficiently. Customers can conveniently install this Variac Type Servo Three Phase Stabilizer in their home, hospital or factory. This is applicable in cement plant, food processing units, flour mills, engineering units, pharmaceutical units, paper mills, etc. Oil Cooled Three Phase Variac Type Servo Stabilizer is installed in the building structure to protects the equipment against short circuit, line losses and overload. Constant voltage can be achieved with this stabilizer. We design and develop this device to be used efficiently and keep the owners at peace. The problem of voltage variations in the mains power supply, can be solved by the device we are offering. The components that make this device are solid state sensing circuit, double wound step up Transformer, motor and SVT Auto -Transformer. The front panel of the device has neon indicator, HI/LO indicator, voltmeter, output adj., auto-manual switch and incr/decr. switch.