Everything You Need to Know about a Servo Stabilizer

Dec 1, 2022 | Transformers | 0 comments

 The servo is an electrical motor that forms an integral part of a stabilizer that has the control and stabilizing capacity of voltage output supplied by the voltage stabilizer regardless of the voltage fed to it. That is why it is called servo controlled voltage stabilizer.

They work based on the servo mechanism. The main component is the servo motor which runs clockwise and anti-clockwise direction to manage voltage fluctuation. The distribution capacity ranges from 230 volts to 415 for single and three phases respectively.

 History of servo stabilizers

 The concept of servo stabilizers came into existence in the year 1962 (during the Indo-China war). During the war, the defence equipment faced massive failure due to voltage fluctuations. Consequently, in 1963, Automatic electric Limited designed and developed the first servo voltage stabilizer in India using the Mercury sensing relays. In the later stages, it was introduced to the open market in 1965 as voltage fluctuation was an overall problem throughout the country.

 Difference between stabilizer and servo stabilizer

Static stabilizers have a minimum correction time of 20-30 milliseconds whereas servo stabilizers have a correction time of 50 milliseconds to 5 seconds with a correction speed of 100V/S. They work on electronic functions based on microprocessors and IGBT(insulated gated bipolar transistor).

 Autotransformers are installed in Servo stabilizers which regulate voltage levels based on primary and secondary windings. This controls the moment of a shaft that enables the servo stabilizer to control the voltage. In static stabilizers voltage regulations solely depends on the reliability of the IDBT power stage.

Components of a servo stabilizer

 a. The components found in a servo stabilizer are autotransformers or otherwise known as dimmer transformers/ continuous variable transformers. The dimmer variable transformer is round in shape. It is made up of silicon CRGO ( cold rolled grain oriented Steel) toy toroidal Core used for the base and copper wire with specific turns ratio according to the capacity. It increases or decreases the voltage fed to the buck-boost transformer.

b. Carbon brush: It is a moving part in a servo stabilizer that is fitted in the shaft to make contact with the dimmers. The wear and tear of the brush depend on the frequent fluctuations of the voltage.

c. Servo Motor: The motor rotates the arm connected to the dimmer clockwise or anti-clockwise in response to the input of voltage.

d. Buck-Boost transformer:- Unlike dimmer, it is rectangular. Bobin is fitted with a GRGO core. It is dipped in varnish for extra protection. It enhances coil life and protects the windings from environmental exposure.

e. Contactor: Its main function is to cut off the servo stabilizer and keep it from exceeding a prescribed limit.

f. MCG/MCCB: MCB (miniature circuit breaker) is used to switch in/off the servo stabilizer and gives short circuit protection. MCCB (molded case circuit breaker) warns against overload.

g. Electronic circuit: it sends signals to various parts of a servo stabilizer like the motor, dimmer, etc.

Types of servo stabilizers

The servo stabilizer transformers are classified into single-phase and three-phase stabilizers. In a single-phase stabilizer, it is further classified as air-cooled and oil-cooled based on the cooling method.

 In a three-phase servo stabilizer, it is classified as a balanced type and an unbalanced type based on the load.

Applications of servo stabilizer

 It is not an exaggeration if one says that servo stabilizers are Omni present. They are present in almost all fields. The servo stabilizer is designed with high-grade materials to ensure strong structure and durability. They are used in industries like flour mills, tube mills, rolling mills, textile industries, paper mills, rubber Industries, footwear and leather, defence, etc. They are also used in food processing units, escalators and elevators and CNC machines (computer numerical control) which need a flawless supply of current in the manufacturing of precision tools.

 In household equipment operations, servo stabilizers have almost become a mandatory investment to protect the day-to-day use of costly electronic goods from voltage fluctuations as the stabilizer easily adapts to single-phase and three-phase connections.

 In Healthcare institutions Servo stabilizers have become dispensable. They are used in the safe operation of treadmills, robotic machines (which are used in conducting micro surgeries), all types of scanning machines and other costly surgical equipment.

 In the field of defence, servo stabilizers are used in operating tanks and armoured vehicles, naval guns, artillery pieces and remote weapon stations as it withstands vibrations and travel of vehicles even in uneven grounds and rough waters.

 Benefits of servo stabilizer

 a. Required power usage and less electricity bills.

 b. Safety ensured.

 c. Minimum maintenance cost.

 d. Improved quality lifespan.

 e. Protection for the equipment.

But a static stabilizer works on electronic function based on microprocessor and IGBT(insulated gate bipolar technology) technology that regulates voltage control.

Export profile of servo stabilizers from India

 India is the second largest exporter of Servo products. The market value of export shipments from India stands at 2.1 k, exported by 546 exporters and purchased by 911 clients. Exports are mainly shipped to Nepal (391) shipments), Kenya (348 shipments) and Uganda. (218 shipments). India stands with 2235 shipments followed by Turkey with 155 and China occupies the third spot with 125 shipments. (Ref:- VOLZA. Updated 22nd November 2022).

 Allied products exported: Stabilizer Hood, stabilizer link, stabilizer bar and link stabilizer.


Globalisation, which has been catalyzed by industrialisation, digitalisation and information technology, is solely dependent on the power supply. Servo stabilizers have carved a niche for themselves by playing a predominant role in providing an uninterrupted power supply in all arenas. Whether it is household or commercial, the role of stabilizers has become like heartbeats. 

EVR Power is one of the leading manufacturers of Servo stabilizer transformers, and also power transformers, distribution transformers, rectifiers and inverters. With their round-the-clock support system, they are able to gain a huge clientele and expand yet more. EVR Power exports its quality products to countries across the world, and their products are low maintenance and very efficient. A high-skilled team of experts works on the design and development of transformers and other electrical and electronic products. 


Submit a Comment