In case, you find that your input voltage is higher even for few hours a day – then you can reduce failure rate of electrical equipment by installing “TPS” AVR& will have following advantages :—

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 equipment’s are designed for 230 Volts (1-Ph) i.e. 400 Volts (3-Ph) and have maximum efficiency at this voltage. These heavy electrical equipment’s 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 electrical motors to overheat and thereby premature winding failure.

It is therefore advisable to install Servo Voltage Stabilizer which results in 60 – 80% reduction in breakdown of motors, contactor coils, bulbs, tubes etc. depending upon the Input Voltage variation and working hours of the plant.

The table below gives approximate quantitative reduction in breakdown of electrical equipment’s by use of Automatic Voltage Regulator at various voltage fluctuation levels.

Input Voltage Range Possible % reduction In Breakdown Appx. Power saving possible
Motor load below 10hp Lighting load Motor load below 10hp Lighting load
380-400 volts Nil Nil Nil Servo stabilizer not  required
400-420 volts 5% 10% 3% 5%
420-440 volts 10% 20% 5% 10%
440-460 volts 40% 40% 7% 20%
460-480 volts 60% 60% 10% 30%


As explained above the electrical equipment’s are generally designed for 230 Volts (1-Ph) i.e. 400 Volts (3-Ph) and have maximum efficiency. Increase or decrease in voltage results in drawing higher current thus increasing the losses of the Motors. These higher losses of electric motors also increase the losses of cables, switches,  transformers and other associated equipment’s. With the stabilized voltage at 390-400 Volts, the extra losses generated due to low / high voltage can be considerably reduced resulting  in energy saving.With the installation of AVR, 10-15% power saving is certainly possible.

REDUCTION IN MDI (Max. Demand Indicator):

There will be definite reduction in MDI by 10 – 15% after the installation of an AVR.  MDI is a multiplication of voltage & current and is half an hour reading.  At higher input voltage, the current of electric motors also increases.  So, the MDI also increases.  For Example:

Consider a 10H.P.Motor

Suppose, current at 400 Volts                         =          12 Amps

Current at 450 Volts                                       =          14 Amps

MDI at 400 Volts = (400 x 12) / 1000             =          4.8 KVA

MDI at 450 Volts = (450 x 14) / 1000             =          6.3 KVA

% increase in MDI at 450 Volts as compared to 400 Volts = ((6.3 – 4.8)/ 4.8) x 100% =      31.25%

Even if the high voltage occurs for half an hour in a month, the MDI increases.  With the installation of the AVR, the voltage will be controlled and MDI will also be controlled.


Whenever the voltage increases above 440 Volts, there is a sharp reduction in power factor at least by square function of voltage. At higher input voltage, (i.e. >400 Volts), excitation current (No Load Current) of the industrial motors increases.  The power factor of no load current is normally (0.2).  So with the increase in voltage, the excitation current also increases which further lowers the power factor. By maintaining constant voltage at 390/400 Volts with help of AVR, there will be definite improvement in power factor by 10-15%.


In case of single phasing, The line current increases by 1.5 times which results in higher current flow through the relays, contractors, cables etc . Due to fluctuating voltage, the Electricians sets the overload relay at 15 to 20% higher to avoid frequent tripping of motors in  starter panels .Thus the relay will take 4-6 minutes to trip in case of single phasing.However higher setting of overload relays have very little safety margin against single phasing and overloading conditions.

During single Phasing, the line current increase, which may also produce sparks and may sometime damage the switchgear and may also cause fire.Further the higher current overheats the motors within short time resulting in burning/damage of motors. The motor particularly of smaller capacity motors say upto7.5 H.P cannot withstand this high current for a long time and in most of the cases it burns out before the relay trips.

With the installation of the stabilizer and maintaining 390/400 volts, the motor will operate smoothly drawing 15-20% lesser current and correspondingly the relay setting can be reduced by 15-20% In case single phasing occurs, the relay will trip in 40-50 seconds. The motor can withstand the high current for this period and will be safe. Also, the relays, contactors, switchgears, etc. incorporated with the motor will be safe

Uniform Quality of end Product & Increase in output

With stabilized input voltage to your sensitive production equipment, you can ensure that your production processes run consistently & continuously, without any interruption / aberration, thus ensuring uniform quality of end product as well as increase in output.


Owing to the high efficiency of  “TPS AVR (> 99% in avg. running conditions) and its associated benefits, the payback period of “TPS AVR is normally within 6-12 months, depending upon the input variation and the number of working hours.

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