IMPORTANCE OF AUTOMATIC VOLTAGE CONTROLLER (AVC):
Voltage variation is today one of the major problems afflicting almost every electricity consumer / industry all across the country. Generally, voltage is low during daytime and high during the night hours / holidays / rainy season. High Voltage phenomenon often goes undetected by consumers, whereas Low Voltage is evidently noticeable. Both, Low and High Voltage, result in excessive power losses of electrical equipment, resulting in their premature failure apart from inflated electricity bills
The growing use of sophisticated electrical and electronic equipments, requiring a near constant voltage supply for efficient operation, makes line voltage regulation increasingly necessary and to finer limits. Thus, AVCs or Voltage Stabilizers fulfill this growing need of providing constant voltage supply.
ADVANTAGES OF AVC:
An AVC resolves 99% of voltage problems automatically, and ensures steady voltage supply round the clock at an effective monthly cost of an electrician. Some key advantages of installing an AVC are:
Up to 80% Reduction in Break Down of Electrical Equipment
Up to 30% Savings in Electricity Costs
Improved Productivity of Plant due to less breakdowns
Uniform Quality of End Product
Reduction in MDI (Peak Demand) & Improvement in Power Factor
80% Depreciation as per Income Tax Act in India (being an energy saving device)
PAY-BACK PERIOD:
As per our customers feedback, the payback period for an AVC is typically between 624 months owing to the aforesaid benefits (depending upon the no. of working hours and input voltage variation.
How to choose between Rolling Type And Variac Type Servo Voltage Stabilizer:
Now that you have opted for a Servo automatic stabilizer, you need to decide which kind of stabilizer you want. Here is a step-by-step comparative analysis between rolling contact type and variac type servo voltage stabilizer.
Mechanism
Movement of the carbon as it moves, it always rolls. As the name suggests the carbon contact used is in form of a Roller. Movement of the carbon as it moves, it always slides. The carbon contact used is in form of a Brush.
Durability of the Carbon Brush
Wear and Tear of the carbon brush is at a minimum in A rolling type Servo Stabilizer due to frictionless and smooth surface of the winding track. In a Variac, wear and Tear of the carbon brush is more due to friction and rough surface of the track, resulting in shorter life.
Better Conduction
Copper conductor used in the case of a rolling type is of Copper Strip and not copper wire; copper strip so used serves as a better current carrying conductor. Whereas, the copper conductor so used is Copper Wire, which comparatively has low current carrying capacity.
Durable Core material used
Core used at Rolling stabilizer is purely Cold rolled Non Grain Oriented or CRGO that too fresh and not the reused one, the core so used is constructed from low loss, cold rolled, grain oriented, annealed laminations of electrical sheet steel conforming to the latest international standards. Core used in Variac type is generally CRNO (i.e. Cold rolled Non Grain Oriented) which has higher losses value in comparison to CRGO. Very rarely CRGO is used and that too made from the reused material.
Easy Assembling
Inspection of the Carbon roller of a rolling type stabilizer can be done without taking out the whole Transformer / Regulator assembly. Only by removing the top cover the condition of the carbon rollers can be observed. Whereas in a Variac type, it is completely the opposite, the transformer has to be taken out.
Backup controller
In the case of failure of the rolling type stabilizer’s automatic controller, the same can be operated manually by raise lower button, in case the motor also fails to work the Hand Wheel provided on the side of the stabilizer can be operated manually and the carbon roller can be positioned to give desired output. While the Variac type has a manual operator, it still misses out on the hand wheel part.
Higher Efficiency :
Efficiency of the Rolling Contact Type Stabilizer is approximately 98% to 99% resulting in minimum losses and lesser electricity bills while efficiency of these Variac Stabilizers is not more than 95% to 96% resulting in more loses and higher electricity bills.
Can be used in any premises
Installation of Rolling Contact Type Stabilizer can be done for Indoor or Outdoor services. Installation of Variac or Dimmer Type Stabilizer can be done only for Indoor services.
Life of a Rolling stabilizer is better than a Variac stabilizer
Life of Rolling Contact Type Stabilizer under normal working conditions is 15 – 20 Years while Life of Variac / Dimmer Type Stabilizer under normal working conditions is approx 3 - 6 Years.
From the above write-up, you must have inferred that Rolling stabilizers are much better than Variac Stabilizers
But VARIAC type has following advantage over Rolling contact linear type is VARIAC has faster Voltage correction speed, lightweight and cheaper in cost.
Rolling contact Linear type Vs Variac based or dimmer type :
Given below are a few of the superior features of our SERVO VOLTAGE STABILIZER as compared to the conventional ones: using square copper section to facilitate more current carrying capacity.
We insist on the use of chain drive allowing the regulating transformer to be driven at relatively higher speeds yielding smooth commutation avoiding potential jamming.
Carbon Roller Assembly Vs ordinary brushes. The torroidal type dimmer has to be cleaned very often because the brushes wear deposit and carbon on the track. The roller assembly used by us yields very low wear with the contact life expectancy exceeding 1,00,000 meters of track level.
In case of jerking loads the normal carbon brush tends to wear off because of its size limitation which would ultimately affect the efficiency of the system, whereas our roller assembly with stands jerks very effectively without hampering the working.
The core is built from grain oriented silicon steel laminations which keeps iron loses to minimum values. The flux density is not allowed to rise to the saturation points point thus reducing output waveform distortion.
Linear type Roller servo withstand an overload of 20 times than normal current for a small period, which is a unique feature in itself. The conventional ones will immediately burn in case of any overloading.
The efficiency of Linear Stabilizer at 75% load is more than 99%.
ADVANTAGES Linear type AUTOMATIC VOLTAGE CONTROLLER
In case, you find that your input voltage is higher even for few hours a day then you can reduce failure rate of electrical equipments by installing Rolling contact linear S AVC & will have following advantages:
REDUCTION IN BREAKDOWN OF ELECTRICAL EQUIPMENTS: 60 80% reduction in breakdown of motors, contractor coils, bulbs, tubes etc. depending upon the Input Voltage variation and working hours of the plant.
ENERGY SAVING: With the installation of AVC, 5-10% power saving is certainly possible. Power losses of any electrical equipment increase at low or high voltage. With the stabilized voltage at 390-400 Volts, the extra losses generated due to low / high voltage can be considerably reduced that will automatically result in energy saving.
You will find from a table in our AVC catalogue that you can achieve power savings of up to 10% on motor load & 30% on lighting load, besides up to 60% reduction in breakdowns.
REDUCTION IN MDI (Max Demand Indicator): There will be definite reduction in MDI by 10 15% after the installation of an AVC. 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 AVC, the voltage will be controlled and MDI will also be controlled.
IMPROVEMENT IN POWER FACTOR: 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 as the voltage increases, the excitation current also increases which further lowers the power factor. By maintaining constant voltage at 390/400 Volts with help of AVC, there will be definite improvement in power factor by 10-15%.
Uniform Quality of end Product& Increase in Throughput: With stabilized input voltage to your sensitive production equipments, 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.
Depreciation allowance @ 80% as per Income Tax Act
PAY-BACK PERIOD:
Owing to the high efficiency of Rolling contact linear S AVC (> 99% in avg. running conditions) payback period of Linear AVC is normally within 6-12 months, depending upon the input variation and the number of working hours.
Variacs Dimmer type STABILIZERS
Torroidal Dimmers are used, wound with max. 8 mm² copper wire. Cross-section area is 3 times lesser. I²R losses are more.
Heat generated is more. Size is bulky. Quantity of oil is more.
Regulators are straight 254 volts type, remaining always in circuit. At any given point, it will contain its max. current.
Light duty carbon brushes are used which are in full contact with the winding. Wear & tear requires change of brushes periodically.
Light duty. Suitable only for partial loads.
Maximum life is 5-8 years if operating at full load.
Prone to damage when working on high capacity motors and jerking loads. Double the capacity is required for such applications.
Overall efficiency max. 95%. Running cost is high as the stabilizer will consume 5% energy itself. A 100 kVA stabilizer will consume approx. Rs.1,00,000 worth of energy per year (assuming 70% avg. running load for 24 hours a day, working 300 days a year).
Warranty 1 2 years. AMC @ 10% of its value thereafter.
ROLLING CONTACT Lineae STABILIZERS
Linear type regulators wound with min. 24 mm² copper strips. Since the cross-section area is more, I²R losses are much less. (R = L/A)
As the losses are less, heat generated is less. The size of the stabilizer is very compact, the quantity of oil less.
Regulators are ± 440 or ± 254 volts therefore half the capacity is sufficient. At max buck or boost position, regulator is out of circuit. No losses at those points.
Graphite Carbon roller assemblies are used, which do not require replacements for at least 8 10 years (or 100,000 meters of travel). There is no wear & tear of the bared copper track.
Suitable for 100% continuous duty cycle. Sufficient overload bearing capacity due to its liberal design.
Life at full load is 15 20 years.
No effect on jerking loads or with heavy starting current machines. Same capacity Stabilizer can be installed.
Over all efficiency is 99% resulting in minimum running cost. A 100 kVA stabilizer will consume only about Rs.20000/- worth of energy per annum (assuming 70% avg. running load for 24 hours a day, working 300 days a year).
Unconditional Guarantee for 5 years. Service network all over the country. Maintenance requirements are minimal & cost very nominal.
For any queries or clarification you can contact me at +91-9165234616 or TheBetterWorldindia@outlook.com
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