|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Introduction
Voltage fluctuation is a common phenomenon in every part of the country. The industrial units running round the clock, usually face the problem of low and high voltage. 90% of industrial load motors . Electric motors draw considerably high current at low & high voltage. This higher current affects the electrical motors ( particularly smaller capacity motors upto 7.5 H.P.) in three ways:
|
- Higher current produces higher losses in electrical motors which causes premature failure winding.
- These higher losses of electric motors also increase the losses of cables, switches, transformers and other associated equipments.
- For smooth continuous operation of motors, overload relays are usually set at 20% higher setting.
|
| Adverse Effects of Single Phasing |
- The line current increases by 1.5 times.
- If the relay setting is at 15-20% higher than actual operating current then the relay will take 4-6 minutes to trip.
- The motor ( particularly smaller capacity motors upto 7.5 H.P) cannot withstand this high current for such a long time and in most of the cases it burns out before the relay trips.
- Heavy short circuit current flows through the relays, contactors, cable etc.
- Under this condition when the relay, contactor trips, they produce sparks and some times burst.
- This further damages the switch gear and in some of the cases may cause fire also.
|
| 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 fot this period and will be safe. Also, the relays, contactors, switchgears, etc. incorporated with the motor will be safe |
| |
|
|
|
Who Needs A Stabilizer
|
 |
The industrial units having acute /higher failure rate of Electrical Equipments such as bulbs tubes, chokes, starter, contactor coils & motors (particularly smaller capacity motors upto 7.5 H.P) etc. should verify that it may be due to HIGHER voltage. You may note down Hourly readings of voltage variation for few days. If you find that input voltage is above 230 volts single phase / 400 volts Three phase even for few hours a day, then you definitely require a stabilizer.
How to Access Higher Losses & Low Power Factor in Industrial Units Without Installing Stabilizer
Note down hourly readings of current and voltage of one motor operating at constant load for 2-3 days. From the different readings you will observe that the current drawn by the motor is minimum at 390/400 volts as compared to the current drawn at other voltages. This means that power consumed by the motor is minimum at 390/400 volts. |
Also note down hourly readings of voltage and K.W. from your Electronic Energy Meter for 2-3 days. From the readings you will observe that K.W. is minimum at 390/400 volts in most of the readings as compared to the higher voltage.
If you find that the above collected details are true then you will certainly have the advantages after installing the Servo voltage stabilizer as mentioned on succeeding page. |
|
| |
| The table below gives approximate quantitative advantages of Automatic Voltage Controller at various voltage fluctuation levels. |
| |
| Input Voltage Variation |
Possible % Reduction In Breakdown |
Possible Appx. Power Saving |
| Motor Load Below 10hp |
Lighting Load |
Motor Load below 10hp |
Lighting Load |
| 380-400 volts |
Nil |
Nil |
Nil |
Nil & no servo stabilizer 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% |
|
Benefits
|
 |
Up to 80% reduction in failure rate of electrical equipment |
|
Energy saving up to 10% (up to 30% on lighting load) |
|
Reduction in MDI |
|
Improvement in Power factor |
|
Uniform quality of end products |
|
Improver Productivity of the plant |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
|