What is Servo Voltage Stabilizer?

Servo Controlled Voltage Stabilizer

Is Servo Voltage Stabilizer or Servo Controlled Voltage Stabilizer Same ?

Yes, Both are the same thing, Only in some part of the country It is popular as Servo Stabilizer, and in some parts, it is called Servo Controlled Voltage Stabilizer.

Some time even it is called Automatic Servo Voltage Stabilizer also

Servo is an electrical motor that is primarily an integral part of the stabilizer, which controls and stabilizes the output voltage supplied by the voltage stabilizer irrespective of the incoming voltage fed to it.

Accordingly, a few people call it as Servo Controlled Voltage Stabilizer while others go short by calling just as a Servo Stabilizer.

What is a Servo Controlled Voltage Stabilizer? Why should I install one?

A Servo Stabilizer is a Servo motor controlled stabilization system that performs optimum voltage supply using a Buck\Boost transformer booster that captures voltage fluctuations from input and regulates current to the correct output. An AC synchronous motor adjusts voltage in clockwise or anticlockwise direction and manages the output voltage with components like control card,dimmer,comparator, transistors, mocs, etc.

Main Components & their Functioning

There are seven main components in a servo voltage stabilizer:-

1. Dimmer (Variable Transformer)

2. Carbon Brush

3. Servomotor – Synchronizing Motors

4. Buck Boost Transformer (Series Transformer)

5. Contactor or Relay


7. Electronic Circuit

1. Dimmer (Variable Transformer) – It is normally round in the shape. Silicon CRGO toroidal core is used for the base & copper wire with specific turn ratio according to the capacity is used. The basic purpose of dimmer is to increase or decrease the voltage which is fed to the buck boost transformer. 50% of the output voltage is increased or decreased by dimmer only.
Let us take an example: If the input voltage is 160V, the dimmer will increase it to 190V & rest of the 30V (since 220V is required to run any single phase load) will be done by Buck Boost Transformer.

2. Carbon Brush – This is a moving part in servo stabilizer, it is fitted in the shaft to make the contact with dimmer. If the input voltage variation is very frequent, this carbon brush will erase early and customer has to replace it very frequently. That is why servo stabilizer manufacturers should use best quality carbon brush.

3. Servomotor (Synchronizing Motors) – Servomotor as the name suggests is the main part of servo stabilizer. The motor rotates the arm connected on the dimmer in clockwise or anti clockwise direction according to input voltage.Buck-Boost-Transformer

4. Buck Boost Transformer – Contrary to dimmer it is in rectangular shape. Bobin is fitted with EI CRGO core. When the transformer structure is built, it is dipped in varnish tank for extra protection.
This type of Insulating varnish also called transformer varnish is put on all the windings used in buck boost transformers to encapsulate them before the servo stabilizer is ready for regress testing. Transformer varnish enhances coil life and protects windings in the transformer from environmental exposure that would otherwise get damaged due to vibrations. This varnish can be used as a great insulator for any coil of wire. Though transformer is there in Isolation Transformer also, But it different from buck boost transformer

5. Contactor – The function of contactor is to cut the output of any servo stabilizer if it exceeds a prescribed limit.

6. MCB, MCCB – The MCB is used to switch on /off the servo stabilizer and gives short circuit protection whereas MCCB is normally for overload protection.

7. Electronic Circuit – As the name suggests, it sends the signal to various parts of a servo stabilizer like motor, dimmer, etc., so it works according to that signal & does their part to correct the voltage.


These are the main components used in servo stabilizer though there are many other parts also like voltmeter, ampere meter, connectors, etc. Give us your email address to know the functioning of each Component.

The Servo stabilizer has definitely an edge over traditional stabilizers.

Basically there are two types of stabilizers, one is relay based and the other is Servo based.

In relay stabilizer, a switch corrects the output voltage accuracy at ±10%. But in Servo, the primary Servo motor corrects supply using buck-boost function. This type of stabilizer is beneficial for high output voltage accuracy. It provides ±1 % voltage output where input voltage alters up to ± 50 %. This type supports up to 5000 KVA & above so it has a higher load capacity.

Ultimately, the major difference between the two is performance as Servo is a stepless correction technologically superior to traditional relay transformers and gives accurate output.

A Servo Stabilizer is a popular replacement for low high rating appliances used in both commercial and residential places, homes and industries that provides unmatched voltage supply to protect your fragile equipments. Servo has both single-phase and three-phase systems coming in Oil cooled and Air-cooled units.


Why do I use a Servo stabilizer?


A Servo Stabilizer is not just a voltage fixing system, but a completely reliable energy device that is advantageous over the traditional relay based stabilizer. We have quite a number of benefits of using Servo:

1. High voltage correction accuracy with output of ±1 voltage correction.

2. Switch less system to adjust fluctuating voltage at desired levels.

3. High load capacity that supports up to 5000 KVA or above.

4. Voltage is based on step less correction.

5. Perfect stabilization for hospitals best for intricate machineries like X-ray machines, CAT scans, radiation and diagnostic equipments.

6. Wide functioning area from schools, offices, homes and industries.

7. Oil cooled and air cooled transformers that fit your budget.

Eventually, Servo stands the winner because of its unmatched performance and longer life features