Managing the Menace of Voltage Variations

Voltage variation is a very common phenomenon. In India, all electrical equipment is designed for 230/400 volts single/three-phase. The input voltage is generally low during day time and high during night hours. Voltage variation is everywhere, at some places it is high/low or sometimes even both (fluctuating).

Effects of high or low voltage

At the high Voltage condition, current of electrical/electronic equipment increases accordingly. This high current increases the losses of equipment resulting overheating the insulation of electrical/electronic equipment and becomes the cause of pre-mature failure of electrical/electronic equipments. It also increases the power consumption & MDI etc.

At low voltage condition, the electrical/electronic equipment does not work/operate properly. Repeated tripping of the system ultimately leads to wastage of time/loss of production.

Automatic Voltage Controller (AVC)

To solve the challenge of voltage variation, Automatic Voltage Controller (AVC) is required. The main part of AVC is the Voltage Regulator.

There  are  two  technologies  of  Voltage  Regulator  available  in  the  world:

  • Dimmer Type Torroidal wound with copper wire and sliding contact carbon brush assembly un-suitable for continuous load with higher losses up to 8% at rated current.
  • Linear Type Vertical Wound with cooper strip and have compensating winding Carbon Rolling Contact Assembly Rolls over the Regulator Coils both side for plus minus purpose for continuous current having trouble free working life more than 15 years with losses less than 1% at rated current.

In 1990 we developed the linear regulator

This is suitable for continuous load with lesser losses i.e. 1% maximum at rated current. The material used in linear voltage regulator i.e. copper, lamination and size is three times the conventional type voltage regulator.

Energy Audit

Any power consumer can do Energy audit or check the voltage variation in their premises with the help of digital power analyzer, which is easily available in the market at a very nominal cost (approx. Rs. 6,000/, with accessories & Software). It records the data after every 15min. interval for 7 days as shown in the chart below:




According to the voltage variation / current pattern, a consumer can decide whether he/she needs the Automatic Voltage Controller or not.

The payback period

The benefit of installing an Automatic Voltage Controller is to reduce the failure rate of costlier electrical/ electronics’ equipment.

The Automatic Voltage Controller is not a power saving device. This is added advantage at high voltage.

The input voltage increases payback period decreases accordingly may be 4-12 months.

Due to not reliable technology of Voltage Regulator available the voltage correction system could not become popular.



B. B. Jindal,
Founder, Jindal
Electric & Machinery Corp

For more information: contact at E-Mail:

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