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Servo Voltage Stabilizer


Introduction of Product

Highly fluctuating AC mains supply is a very common phenomenon in India and difficulties caused by them are well known. The stable Input supply is a basic necessity in the absence of which sophisticated equipment do not give optimal performance. Major industrial loads are inductive in nature (i.e .A.C. Motors) and they draw considerably high current at High & Low voltages resulting in higher losses which in turn increases the temperature of motors thereby reducing the motor life. Other equipments that are affected by high & Low voltages are Lighting loads(Bulbs & Tubes) Air conditioning plants Elevators & lifts ,Medical equipments etc.

For overcoming this ‘Shakti’ manufacture state of art ‘Servo Voltage Stabilizer’ which encure constant output voltage thus providing complete protection and optimum efficiency of all electrical & electronic equipments. With the installation of shakti stabilizer’and maintain output voltage of 400V 3-0 /230V, 1-0 within 1% the motors operate smoothly without drawing excess current.

Shakti’s 3-phase stabilizers are manufactured using individual controls for each phase thus making it suitable for unbalanced input voltage and unbalanced load current. Balance type unit can also be supplied on demand.


Effects of Voltage Unbalance

The main effect of voltage unbalance between phases is damage to motor due to excessive heat.Voltage unbalance can create a current unbalance of 6 to 10 times the magnitude of voltage unbalance. Consequently this current unbalance creates heat in the motor winding that breaks down motor insulation causing cumulative and permanent damage to the motor. Figure shows the percentage of temperature rise as related to voltage unbalance.

The relationship is exponential & approximately increases by twice the square of the voltage unbalance.

In order to avoid frequent tripping of overload relays the operator sets the relays at higher than actual limits to continue the production . The motors cannot withstand this higher current for long time and in most cases the motor burns out and also damages controlling relays/contactors.

The most suitable option is to use servo stabilizers having separate control system on each phase (Unbalance type). This will take care of both unbalanced and balanced input supply providing balanced 3-phase supply at output.


Benefits of Servo Voltage Stabilizer

Maximum load in industries consist of motors, heaters & compressors. At high voltage they draw higher current thus increasing the power Consumption & MDI and reducing the power factor. Electrical equipments are designed for 230 Volts (1-Ph) i.e. 400 Volts (3-Ph) and have maximum efficiency at this voltage. These heavy electrical equipments draw considerably more power at higher voltage thus increasing the electricity bill of the industry. Similarly in the case of bulbs & tubes the percentages increase of power consumption will be more than double the percentage increase of voltage. The higher voltage also results into higher losses causing higher breakdown of Motors Lightings & all other electrical equipments.

Servo stabilizer can give saving of upto 15% on power consumption & reduction in breakdown of electrical equipments upto 80% if voltage supply is above the recommended voltage and higher efficiency of your equipments if voltage supply is lower than the recommended voltage.


Input voltage variation Percent Reduction in Breakdown Possible Approximate Savings in Power Consumption Possible
380 to 420 Volts Up to 10% Reduction in breakdown of electrical equipments. Up to 5%
380 to 440 Volts Up to 20% Reduction in breakdown of electrical equipments. Up to 7%
380 to 460 Volts Up to 60% Reduction in breakdown of electrical equipments. Up to 10%
380 to 470 Volts Up to 80% Reduction in breakdown of electrical equipments. Up to 15%


Salient Features of Servo Stabilizer


  • Fully solid state Micro Processor Based Digital control circuit.
  • No waveform distortion.
  • High efficiency.
  • Auto / Manual operation facility.
  • + 1% regulation of output.
  • No phase shift.
  • Output adjustment possible.
  • High speed of correction.
  • No effect on power factor.


Point wise benefits of Servo Voltage Stabilizer


  • 10 to 15 % saving in electricity bill ( More than 25 % on lighting load )
  • Up to 80 % reduction in breakdown of electrical equipments.
  • Reduction in MDI by 10-15 %
  • Improvement in Power factor
  • Payback period within 6-12 months
  • Improved production of the industry.
  • Uniform Quality of final product.


Technical Specifications


Capacity 10 to 50 kva 1 ph   10 to 2000 Kva 3 ph or as required
Input Voltage Range 300-460/320-460/340-460/350-450 Volt 3 ph or as required
Output Voltage 220/230/240V 1-ph, 380/400/415 V 3-ph
Regulation + 1%
Operating Frequency 50 Hz + 5%
Efficiency 98-99.5% (Based on Capacity & Range)
Effect of Load Power Factor Nil
Wave Form Distortion Nil
Cooling Air / Oil
Location Indoor / Outdoor
Correction Speed Upto 60V per sec 1 ph and 105V per sec 3 ph
Response Time Less than 10 ms
Duty Cycle 100% Continuous
Control Fully Solid State Digital Control


Basic Concept

“Shakti” Servo Stabilizer has a solid state circuit which controls the servo motor. The motor is mechanically coupled to the arm of continuously variable auto transformer which feeds to the primary of a Buck/Boost transformer.The stabilizer output voltage is compared with the reference voltage and the resultant error signals control the servo motor providing a true proportional control system rather than On/Off circuit.


Optional Accessories


  • MCCB / MCB
  • High & Low Voltage Cut -off Output.
  • Electronic Overload Protection.
  • Push Buttons for manual rese.t
  • Single Phasing Preventor.
  • Display of output Load Current.


Fields of Applications


  • All kinds of Industries like Textile ,Cement Plants ,Cold Storage ,Paper, Oil & Ginning ,Food Processing , Footwear Leather, Mining Dairy Chemical,Automobile,Printing Press, Newspaper etc.
  • And for Hospitals , Nursing Homes , Banks , Colour Labs, ,Jewellers , Hotel, Resorts, Restaurants, Defense, Telecom installations ,Buildings, Commercial Complex, Show Rooms, Residential Installations etc.
  • Also for Elevators, AC Plants , Compressors , Medical Equipments Computers Xerox Machines High Power Music system , CNC Machines etc.