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Automatic Relay Voltage Regulators/Stabiliser


AVR's save on the cost associated with equipment damage caused by poor voltage levels. We manufacture best-in-class copper winding automatic stabilizer in wide input range.

Key features
  • Electronic circuitry is zener controlled.
  • Only IC, silicon transistors are used for reliability at high temperatures.
  • High quality electromagnetic relays are used which operate silently without producing thumping sound during voltage fluctuations.
  • Stability with temperature changes.
  • Safe at an ambient temperature from 10 degrees to 50 degrees Centigrade.
  • Wide input range.
  • Outer cabinet stove enameled after proper anti rust phosphate process.
  • Low/High tripping facility and Time Delay Relay provided at an extra cost.
  • All transformers are vacuum impregnated with high class varnish for reliability and long life.
  • All AVR's designed by us comply with the latest safety codes of practice





160-280 Volts

200 - 240 Volts

0.25 – 10 KVA

145-280 Volts

200 - 240 Volts

0.25 – 10 KVA

130-280 Volts

200- 240 Volts

0.25 -  10 KVA

110-280 Volts

200 - 240 Volts

0.25 – 10 KVA

90-260 Volts 200 - 240 Volts

0.25 – 5 KVA  


Note: An output/input switch is provided on every stabilizer. Press this to ascertain input voltage at any time. This will not interfere with the working of your stabilizer. A pilot lamp indicates that the stabilizer is in operation. This switch should normally be kept on the output side.


As both high and low mains voltage can damage your electrical equipment, the JYOTI brand AVR is designed to monitor and correct incoming supply continuously. If the voltage rises or drops, the AVR will stabilize the output to ensure that the voltage reaching your equipment remains within the operating range of the unit. The AVR also protects your electrical equipments against voltage fluctuations. By using the AVR you will ensure a stable and clean voltage supply to your equipment. Depending on the rating of your AVR, it is suitable for all electrical and electronic appliances, including: Fridges, Photocopiers, Laser Printers, Coolers, Televisions, Satellite Equipment, and Computers, Fax machines, Air Conditioners, Video Equipment, Domestic pumps


  • Follow safety instructions while installing and operating them.
  • To avoid the risk of shock do not expose the AVR to rain, moisture or liquid spillage.
  • Before attempting to use the AVR ensure that the total loading of your stabilizer does not exceed the maximum rating of the AVR. If in doubt consult your electrician.
  • Do not insert any object into the ventilation slot.
  • Do not install AVR's inside closed cupboards and do not allow papers or other materials to be piled on top.
  • Do not attempt to dismantle the AVR .Doing so will invalidate the guarantee.


Automatic Servo Voltage Regulators Stabilizers


How to choose a Servo Stabilizer

There can be three types of loading conditions in an electrical system
a. All the loads are of three-phase nature.
b. There is a mixture of three-phase and single-phase loads.
c. All the loads are of single-phase nature.

In view of the above facts and the guiding principle, the choice of a three phase stabilizer for condition (a) and (b) falls on balanced load type stabilizer.

An unbalanced load type stabilizer should be used only for option ©

In spite of the selection of the type of 3- phase stabilizer, it is imperative to point out that the neutral needs to be solidly grounded for proper functioning of the electrical system.

Choosing the right KVA of a Servo Stabilizer
Some thumb rule conversions factors for choosing the right KVA of the Servo Stabilizer.

a. KVA of Stabilizer = H.P. of lift * 3
b. KVA of Stabilizer = Tonnage of A.C. plant * 2
c. KVA of Stabilizer = H.P. for Resistive loads
d. KVA of Stabilizer = H.P. or K.W./ Power factor for Reactive loads.

The stabilizer KVA needs to ascertained and designed using the pack conditions.



Single Phase     

 Three Phase

Input Volts*


280 – 460V / 300 – 460V

Output Volts*

230 +/- 1%

380/400/415  +/-1%





48-52 Hz

48-52 Hz

Wave Form Distortion




Depends on type of cooling and IS Specifications


Designed for indoor tropical use



CNC Machines

Air Conditioning Plants

Telecommunication Networks

Motor Loads

Data Processing Equipment

Bio Medical Equipment

Drives, PLC’s

Induction Heating


Defense Application

Industrial Units

Lighting Loads

Residential/ Offices

Farm Houses

R & D Institutions

Sophisticated Laboratories




Auto/Manual Switch

Low/High voltage trip

Voltmeter on Output

Short Circuit Protection

Output Volts Adjust

Single Phasing Protection

Lower/Raise in manual

Input/Output Voltage Metering

Mains Indication

Reverse Phase Protection


Isolation Transformer

Selector Switch (30 units)

Temperature Gauge


Silica Gel breather


Change over Switch


Oil drain valve


Constant Voltage


CVT maintains voltage using Ferro-resonance principle where large changes in input voltage result in small changes in output voltage. Our transformers are built to filter any distortion
Key features

  • Instantaneous regulation
  • Over current protection
  • Stability with temperature
  • Filtration of all spikes and over voltages
  • Isolated supply
  • High reliability as no semiconductors/ moving parts used
  • Constant voltage over a large input range
  • Inherent short circuit protection
  • Maintenance free




Input Volts

160-300V AC

Output Volts

220/230V AC +/-1%


50 Hz

Load Regulation

Better than 2%

Current Lamination


Full Load Efficiency

87% (approx)

Transformer Type


No Load Loss

approx 15-22% of the rated VA capacity

Frequency Variation

106% change in output voltage for every 1% change in frequency




Data Processing Equipment

Telecommunication Systems

Electrical & Electronic

Biomedical Equipment

Color Photography Labs Testing Labs

Note:- CVT can be only designed up to a limitation of 5 KVA.


  • Place the CVT away from magnetic storage and display devices like monitors, diskettes, tapes etc.,
  • Keep it in such a place that plenty of air circulation is provided to it.
  • Make sure that there are no loose connections.
  • Do not place anything on top of CVT during operation.
  • Switch off CVT when frequency variation exceeds 50+/-1Hz
  • Do not use the highly inductive loads like motors.

Isolation & Control


Isolation transformer is one that contains two windings: Primary and Secondary winding, that are separated from each other but wound on the same Iron core. The secondary that governs the output is, in this manner, separated from the input. Input and output are totally independent of each other except for the magnetic linkage between the two.

Power line isolation can be provided to avoid component damages when using test instruments.

There are two kinds of Isolation Transformers:
1. Shielded type Isolation Transformer

2. Ultra Isolation Transformer

The results of an Ultra Isolation transformer are:

  • It provides a perfectly balanced neutral at ‘zero’ potential and neutral can be used by grounding it.
  • The supply of the output is free from all surges/spikes and so called electrical noise, which predominantly is present on the input side.
  • Since the output is totally isolated from the input, any short circuits or faults on the primary side are not reflected on the secondary, thus avoiding damage to the sensitive electrical equipment.


Due to Delta/Star three limbed construction the input currents get fairly balanced even though there is unbalancing of loads on the output.