Automatic Servo Voltage Stabilizer / Controller

Bharti’s Automatic servo stabilizer provides protection against fluctuation / unbalanced voltage. Bharti’s automatic servo stabilizer resolves 99% voltage problems and gives stable voltage supply 24/7. Rolling contact type regulator is used in servo voltage stabilizer which is rugged built and gives the maintenance-free performance.



Fluctuations in the voltage is a constant feature of the Electricity supply we get. The constant fluctuation of a voltage leads to frequent breakdown and higher rejection in the end product. We know that 90% of the industrial load is of the motor. It draws high current at high & low voltage. This higher current produces higher losses in electrical motors. These losses in the motor increase the losses in Cables, Switches, Transformers, and other associated equipment.

This higher current affects the electrical motor (particularly smaller capacity motor up to 7.5 H.P)in 3 ways

  • The higher current produces a higher loss in the electrical motor which causes premature failure of winding.
  • These higher losses of electric motor also increase the losses of cable, switches, transformer & other associated equipment.
  • For smooth continuous operation of the motor, the overload relay is usually set at 20% higher selling.

With the installation of the stabilizer & maintains 390/400 volt, the motor will operate smoothly drawing 15-20% lesser current & correspondingly the relay setting can be reduced by 15-20%.


The Buck/Boost and Regulator Transformer winding is built from paper covered electrolytic copper strip or enameled copper conductor (Dried in the oven). The core is built of high-grade cold-rolled grain-oriented silicon lamination (CRGO) to minimize iron losses. All components of equipment mounted on a framework of M.S. housing are fitted with cooling pips to provide natural cooling.

We provide a vertical Rolling Contact types voltage regulator with having sections and paper covered copper strip and fitted with carbon roller assembly which offers higher reliability than ordinary carbon brushes. It is also built with high-quality meter switches and indicators.

It is designed for 30-35 Degree Centigrade above ambient suitable for any kind of ambient temperature condition. Oil which is used as a coolant is of IS: 335 standards being used & it is properly filtered before topping.

In spite of best efforts, no state electricity board can ensure the constant voltage to the customer because of long and inadequate distribution lines and irregular load patterns on distribution transformers. Generally, Voltage is low during day time and high during night hours. Moreover, on holidays, peak hours, rainy days, and when agricultural and Industrial load is switched off, the voltage rises sharply which is more dangerous.

This higher current affects the electrical motors (particularly smaller capacity motors up to 7.5 H.P.) in three ways:
1. The higher current produces higher losses in electrical motors which causes premature failure of winding.
2. These higher losses of electric motors also increase the losses of cables, switches, transformers & other associated equipment.
3. For smooth continuous operation of motors, overload relays are usually set at a 20% higher setting.

With the installation of the Servo Controlled Voltage Stabilizer and maintaining 390/400 volts, the motor will operate smoothly drawing 15 – 20% lesser current


BHARTI’S Servo Stabilizer is manufactured as per IS: 9815 and primarily consists of the following:

1. Liner Plus / Minus Type Vertical Rolling Contact Voltage Regulator
In our regulator, we are using a heavy section of electrolytic grade rectangular copper strip instead of copper wire to minimize the losses & increase the efficiency of the equipment. We are also using self-lubricating Carbon Roller Assemblies instead of ordinary Carbon Brushes which offers more reliability and trouble-free performance of the equipment.

2. Double Wound Buck / Boost Type Series Transformers
In our Buck / Boost transformer, we are using CRGO lamination to minimize iron losses and coils of Buck/Boost transformer are wound with heavy section of multi strips electrolytic copper to minimize copper losses for getting better efficiency of the equipment.

3. Electronic Control Circuit and Meter Panel
BHARTI’S Automatic Voltage Controller consists of a very simple electronic control circuit for monitoring and controlling voltage, repair & maintenance of which is very easy.

The regulator and Buck / Boost transformer are oil-cooled, housed in the same or separate sheet steel tanks. Radiators are provided for effective cooling. The coils of voltage regulator & Buck / Boost Transformers are vacuum impregnated and oven dried as per IS.

Standard Fitting & Accessories:
  • -Rating Plate
  • -Lifting Lug
  • -Drain valve
  • -Oil Level
  • -Oil Filling hole and plate
  • -Wheels
  • -Control MCB’s [1.0 Amp for motor load & 0.5 Amp for voltmeter & indicators]
General Specification:

Bharti’s Automatic Servo Stabilizer is available in a wide range and various models. The standard three-phase models are suitable for balanced and unbalanced supply and loads. The standard model confirms the following specifications are as follow:

  • Input Voltage :300-460V 320-460V 340-460V 360-460V.
  • Efficiency : Better than 99%.
  • Output Voltage :400V, +/- 1%, Phase, 50HZ.
  • Ambient: 0-35°C max relative humidity up to 90%
  • Environment: Designed for Indoor tropical use
  • Waveform distortion: Virtually Nil.
  • Duty Cycle: 100% Continuous.
  • Correction Rate :8-10V/Sec. (Up to-500KVA).
  • Mounting: On Uni-directional wheels.
  • Cooling: Air Cooled/Natural Oil Cooled.
Comparison between Bharti’s make & Conventional make Automatic Voltage Regulator:
Bharti make roller type RegulatorConventional make with carbon brush Regulator
Suitable for 100% continuous duty cycleSuitable only for partial load 50-60%
Power consumption is 0.5 to 1.5% depending upon the model & input voltage variation.Power consumption is 2-7%
Life at full load is 15-20 yearsMax. life is 3-5 years at full load
Life at full load is 15-20 yearsMax-losses in full Buck/Boost condition
Negligible losses at full Buck/Boost conditionsNormal guarantee/warrantee for one year
5 years unconditional guarantee in India.The heat generated is more. The size is bulky. The quantity of oil is more.
As losses are less, heat generated is less. The size of the stabilizer is very compact. The quantity of oil is less.


1. Save Energy.
2. Fewer production losses and better efficiency in the plant.
3. The induction motor operates at high efficiency.
4. Improvement in power factor & reduction in MDI.
5. 80% depreciation as per Income tax in India Only.
6. Reduction in breakdown of electrical equipment.


We can use stabilizer for various kind of application such as:

1. Engineering Units
2. Rice Shellers
3. Cold Storages
4. Textile Mills
5. Paper Milles
6. Rolling Mills
7. Footwear and Leather Units
8. Distilleries & Beverages
9. Rubber/Plastic Industries
10.Tea Estates 11. Pharmaceutical units
12. Cement Mills
13. Flour Mills
14. Hospitals
15. Hotels/Clubs


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