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Save money on UPS AMCs? Connect OVCD before UPS to reduce breakdowns and replacement!!!
As UPS / inverter dealer you might handling a lot of service issue during warranty and AMCs. Breakdown during AMC period is tiresome work and will result in loss of revenue because of frequent visits
Voltage is dynamic in nature i.e. it changes every second in response to connected load.
Switching of loads will cause over voltage and spike in the system and that can damage your UPS/ inverter over a period of time. you need something before the UPS to protect it and increase its life.
UPS parts are now a days difficult to procure if they are out of warranty. Obsolescence of part is also a big problem. eg. you may find it difficult to find spare PCBs of UPSs older than 10 yrs.
Even if you repair the parts it is no guarantee as to how long until next problem.
This is where OVCD becomes an important friend for UPS.
OVCD is designed to withstand 440V for indefinite period of time and that is its biggest strength
Features of OVCD:
- Protection up to 440 volts( neutral open protection)
- Withstand up to 6000v spikes
- Smart start( power on delay)
- Under/over voltage protection
- No wave form distortion
- spike protection upto 6000V
- type 2 surge protection ( optional)
- Single phase preventor ( for 3 phase systems)
- Phase reversal protection( for 3 phase systems)
How it works :
OVCD is connected at before the equipment in use. Incoming current will first pass through OVCD then into the equipment. OVCD continuously monitors the line voltage. Whenever the voltage is above or below the set voltage limits the OVCD simply cuts the voltage to the equipment thereby saving it from the line disturbance. It reacts within fraction of second to the disturbance.
The main feature is that OVCD is the only protection device which give nuetral open protection. i.e OVCD can withstand the voltage even as high as 440 Volts.
Most of the equipments will burn or get damaged at such voltages.
It however does not stabilize the voltage as in the case of other devices in the same category like Stabilizer, CVTs.
When the voltage returns to normal , the OVCD resumes the supply to the equipment with short power-on delay of 3 seconds(configurable). This feature is called the Smart Start. It prevents the initial harmful transient that may damage the Equipment.
Our product is used by significant number of MNCs in India like Emerson Network Power, Numeric systems, Delta Energy, DB Power, Asia Powercom , Techser and many more.
Our product has helped them to reduce the no. of events of product breakdowns by more than 75% and thereby reduce their operating cost.
We will be glad to provide you a sample test device and provide you with further information you may require on this unique product.
We can even customize the product to suit your requirements. We have special models for 3Phase in- 1 phase out UPS.
please whatsapp us on 9769996205 or write your queries to us below
Six Power Viruses
You’ve heard about the dangers of software viruses. But did you know that power viruses can do just as much damage to your system? And that a typical office experiences as many as 6,000 power viruses or more, every year?
Some of these power disturbances are obvious, some are almost unnoticeable, but they all cause problems that can seriously damage your productivity, from lost data and lock-ups to communications errors and hardware failures.
|Common-mode voltage problems
Probably the most serious virus facing computer users today, common-mode voltage problems can cause unexplained data losses, glitches, system failures and “no trouble found” service calls. The only way to immunize against common-mode voltage is to install a power conditioner or UPS that has an isolation transformer output.
This virus is spread by electrical neighbors such as electronic lighting ballasts, appliances, printers, photocopiers and even other computers. Over time, and in connection with low-voltage spikes, noise can wear away electrical components and cause them to fail for no apparent reason.
|Voltage spikes and impulses
Like electrical noise, this virus is also spread by equipment inside your facility. When elevators, motors or air conditioners stop and start, they can cause sudden large increases in voltage inside the electrical system. Other causes include electric utility switching and lightning strikes (which can cause transients so intense they literally “blow up” sensitive electronics).
In the past, unregulated voltages wreaked havoc with linear power supplies, making it hard for computer-based equipment to function. Failures were common. But thanks to the switch-mode supplies used in today’s computers, today’s systems have developed their own immunity to voltage regulation viruses. (This immunity is a by-product of the same technology that makes switch mode supplies smaller and more economical.)
Fiber optic connections are one means of protection, but if your system uses ordinary communications wiring and connections, you need to immunize it against this often unrecognized but very dangerous virus.
Common electrical terms
Many a times, when we are deciding to buy a UPS or and electrical equipment , we are bombarded with a lot of technical Jargons . This is just glossary of common electrical terms in an attempt to De-mystify the Jargons. This will work just like an dictionary .. just technical one
Alternating current (AC): An electrical system in which voltage polarity and current flow alternates direction on a regular basis. Your home is an example of a system that is powered by AC.
Amp: A unit of electrical flow. In a water system, the flow of millions of water molecules would be expressed in terms of gallons per minute. In an electrical system, the flow of millions of electrons is expressed in terms of amps or amperes.
Apparent Power: The amount of power that is apparently consumed by a load. Apparent power is measure in VA or volt-amperes and is calculated by measuring the current consumed by the load and multiplying it by the voltage powering the load.
Common Mode Voltage: A voltage of any amplitude or frequency that is measured between the phase conductor and the ground conductor or the neutral conductor and the ground conductor. Neutral to ground voltage is a common mode component that frequently causes computer system malfunction. Neutral to ground voltages should always be limited to .5 volts (one half of one volt) or less.
Constant Voltage Transformer: Maintains a relatively constant output voltage for variations up to 20% in the input voltage. CVT’s are frequently a ferro-resonant style of transformer in which the voltage is regulated by means of current stored in a magnetic field. CVT’s are generally high impedance devices that are unsuitable for most modern computers with switch mode power supplies.
Current: The “flow” of electricity. Much like water, a current will follow the path of least resistance. As a result, electric current always finds the easiest path to ground. Current is measured in amps or amperes.
Dedicated Circuit: An obsolete method for providing clean, noise free power to a computer system. A dedicated circuit is one in which dedicated phase, neutral, and safety grounding conductors are run continuously from a distribution panel to an electronic load. The conductors may service only the dedicated load and the phase conductor must have its own circuit breaker. Furthermore, the dedicated conductors must run in their own dedicated metallic conduit or raceway with no other conductors present. The neutral and ground conductors may not be “daisy chained” or shared with any other circuit. The ability of dedicated circuits to guarantee a noise and disturbance free environment is insufficient for the high processing speeds, low operating voltages, and mission critical nature of modern technology.
Direct current (DC): An electrical system in which current flows in one direction only. A battery is an example of a direct current source.
Dip: See “Sag”.
Disturbance: Any departure from the nominal values of the power source. Disturbances can include transients, electrical noise, voltage changes, harmonics, outages, etc.
Drop: A slang word sometimes used to describe voltage sags or under voltages.
Flicker: A voltage variation of short duration but long enough to be noticeable to the human eye as a light flicker.
Frequency: In an AC system, the value of the voltage sinewave rises from zero to a maximum, falls to zero, increases to a maximum in the opposite direction, and falls back to zero again. This would describe one complete cycle. The number of complete cycles occurring in one second is called frequency. The General Conference on Weights and Measures has adopted the name hertz (abbreviated Hz) as the measurement of frequency. In North America, the frequency is 60 Hz. In Europe and most of Africa and Asia it is 50 Hz.
Glitch: A slang term for a voltage transient or voltage variation that causes equipment to misbehave..
Grounding Conductor: The physical conductor connecting the chassis of an electrical or electronic device to the electrical system’s grounding means. Sometimes referred to as the safety ground, this conductor may be a green insulated conductor, a bare copper wire, conduit, gutter or raceway. The purpose of the grounding conductor is provide a low impedance pathway for fault current in the event of a short circuit so that a circuit may be quickly de-energized to prevent a fire hazard or electrocution.
Grounded Conductor: Refers to the neutral conductor of the electrical system, which is bonded to the facility’s utility field earth reference in order to reference the facility electrical system to ground.
Harmonic: A whole multiple of the basic power frequency. On a 60 Hz system the 2nd harmonic is 120 Hz, the third harmonic is 180 Hz, the fourth is 240 Hz and so on.
Harmonic Distortion: The alteration of the normal voltage or current wave shape (sine wave) due to equipment generating frequencies other than the standard 60 cycles per second.
Impedance: Impedance is the opposition offered by a material to the flow of an electrical current in an AC electrical system. Impedance has two parts – resistance and reactance. Impedance is measured in ohms.
Interruption: See “Outage”.
Inverter: Device that converts direct current (DC) power into alternating current (AC) power.
Isolated Ground: An insulated equipment grounding conductor that is run in the same conduit as the supply conductors. This conductor is insulated from the metallic raceway and all ground points throughout its length. An isolated grounding conductor may only be connected to the grounding of the electrical system as a point where the facility neutral (grounded conductor) is bonded to ground. An example would be at the service entrance or at a distribution sub-transformer.
Isolation Transformer: A device that electrically separates and protects sensitive electronic equipment by buffering electrical noise and re-establishing the neutral-to-ground bond. By virtue of the neutral-to-ground bond, isolation transformers eliminate neutral-to-ground voltage – one type of common mode disturbance.
Line Conditioner: A device that provides for the electrical power quality needs of the connected electrical or electronic load. In the case of a linear power supply, a line conditioner might be a voltage regulator. In the case of a switch mode power supply, a line conditioner might be an isolation transformer with a noise filter and surge diverter. In the case of a simple electrical device like a motor, a line conditioner might be as rudimentary as a surge diverter. The term line conditioner is frequently misused. It must be understood that not all line conditioners function alike, and the capabilities of a line conditioner must be matched to the power quality needs of the connected load.
Linear Power Supply: A power supply which converts AC power into the DC power that is needed to operate an electronic circuit. In a linear supply, the AC voltage is first stepped down, then rectified, and then regulated using a series regulation device. Linear supplies obtain their name from the fact that there is a linear relationship between the value of the AC sine wave voltage and the power supply’s consumption of current from the AC circuit. Linear power supplies are generally less efficient because the series regulator dissipates large amounts of heat in the process of producing and regulating the DC output voltages. In addition, linear mode power supplies may require well regulated AC input voltage. One benefit of linear power supplies is that they produce little electrical noise.
Mission Critical Load: Devices and equipment identified as important or essential to the safety of personnel or the economic health of a business.
Momentary Outage: A brief interruption in power commonly lasting between 1/30 (2 cycles) of a second and 3 seconds.
Nines of Reliability: The reliability of an electrical system is a combination of both its availability (freedom from outages) as well as it’s quality (freedom from disturbances). Reliability is expressed in percentages. 99% would be expressed as two 9s of reliability. 99.9% would be three 9s reliable, 99.99% would be four 9s reliable and so forth. The average well managed electrical system in North America has about three 9s of reliability. In a 24 x 7 operation, that translates into about 88 hours per year in which the availability and quality of the electrical system are unsatisfactory to reliably power a mission critical electronic load.
Noise: An unwanted high-frequency electrical signal that alters the normal voltage pattern (sine wave). Noise may be either high amplitude or low amplitude.
Normal (Nominal) Voltage: The normal or contracted voltage assigned to a system for determining voltage class.
Normal Mode Voltage: Any voltage (other than fundamental 50 Hz or 60 Hz) that is measured between the phase conductor and the neutral conductor in a single phase system or between any two phase conductors of a three phase system. Normal mode voltage can be any amplitude or frequency. Normal mode noise voltages can interfere with the reliable operation of a computer system or degrade and destroy components. Normal mode power disturbances should be limited to 10 volts or less.
Ohm: A unit of resistance and impedance.
Ohms Law: The relationship between voltage, current and resistance in a DC circuit. If two values are known the other can be calculated. This relationship is expressed many different ways. The basic relationship is voltage (V) is equal to current (I) multiplied by resistance (R). Ohm’s law must be applied in a modified way to AC circuits. AC circuits have impedance rather than resistance. Impedance causes AC circuits to exhibit power factor, which must be factored into any calculations
Outage: Complete loss of electrical power.
Overvoltage: An increase in voltage outside the normal voltage levels (10% or greater) for more than one minute.
Phase Relationship: The timing relationship between voltage and current. If voltage and current cross through zero in a cycle at the same time they are said to be in phase. Phase differences are expressed in degrees. A cycle is 360 degrees. In a totally capacitive circuit, current leads voltage by 90 degrees. In a totally inductive voltage leads current by 90 degrees. In a circuit that is purely resistive, voltage and current are in phase.
Power Factor: The ratio between Watts and Volt-Amperes. This ratio is generally expressed as a decimal fraction. A power factor of 1.00 is unity.
Reactance: Reactance has two components, capacitive reactance and inductive reactance. The values of reactance are determined by the values of the individual capacitor or inductor as well as the frequency of the current flowing in the circuit.
Real Power: The amount of power that is actually consumed by the load. Real power is measure in watts and is calculated by measuring the current consumed by the load and multiplying it by the voltage powering the load and then multiplying by the power factor of the load.
Rectifier: A device that converts alternating current (AC) power to direct current (DC) power.
Reactive power: Reactive power is the difference between apparent power and real power. It is calculated by subtracting real power from apparent power. Reactive power is measured in VAR (volt-amps reactive) or kVAR (kilovolt/amps reactive)
Resistance: The opposition offered by a material to the flow of a steady electrical current in a DC circuit. Resistance is measured in ohms.
Sag: Any short-term (less than 1 minute) decrease in voltage.
Spike: See “Transient”.
Standby Generator: An alternate power supply usually driven by a gas or diesel engine.
Surge: A sudden dramatic increase in voltage that typically lasts less than 1/120 of a second.
Surge Protective Device (SPD): A device that is designed to limit instantaneous high voltages. Also known as a surge suppressor, surge arrestor and transient voltage surge suppressor (TVSS). These units are satisfactory for reducing the amplitude of catastrophic events. However, they function by diverting excess voltage to the safety ground of the electrical system. In the process they create a common mode disturbance which can disrupt the function of microprocessor based electronic systems.
Swell: Any short-term (less than one minute) increase in voltage.
Switch Mode Power Supply: A power supply technology in which the AC power is converted into DC power for use by an electronic system. SMPS technology uses switching transistors operating at very high speed to keep a capacitor reservoir sufficiently charged to produce the appropriate DC voltage needed by the electronic circuit. SMPS technology is very efficient because it does not utilize the “lossy” series regulator found in the linear power supply. Current is consumed from the circuit only when the charge state of the capacitor reservoir requires it. SMPS technology is “constant power” in that when line voltage decreases, the supply’s current consumption increases and when line voltage increases, current consumption decreases. SMPS technology is relatively immune to voltage regulation issues. However, the technology does not employ a stepdown transformer on the front end, which means that it does not satisfactorily isolate the electronic system from the electrical supply. SMPS technology produces electrical noise as a result of the high speed function of the switching transistors.
Transient: See “Surge”
True Power: See “Real Power”
TVSS: See “Surge Protective Device”
Undervoltage: A decrease in voltage outside the normal voltage levels (10% or greater) for more than one minute.
Uninterruptible Power Supply (UPS): A system designed to automatically provide power in the event that utility power is interrupted. A UPS may be standby, line interactive, or on line. A UPS is not necessarily a power conditioner, and care must be taken to ensure that the UPS provides all the power quality requirements that are needed.
Volt: A unit of electrical pressure. In a water system pressure might be expressed as pounds per square inch. In an electrical system, the pressure that causes electrons to move is called voltage. The voltage found in most homes is 120 and 240 volts. Businesses will typically utilize voltage at 120 and 208, or 277 and 480 volts.
Volt-Ampere (VA): The product of volts times amps. A kilovolt-ampere (kVA) is equal to one thousand volt-amperes. VA is also known as apparent power.
Voltage: The electrical “pressure” that creates the flow of current.
Voltage Regulator: A device that maintains output within a desired limit despite varying input voltage. These devices usually provide little to no protection against voltage transients or noise.
Watt (W): A unit of power equal to the product of the value of current of one ampere flowing in phase with the pressure of one volt. A kilowatt is a thousand watts. Watts are an expression of real or true power.
Watt-Hour (Wh): A unit of energy equal to the power of one watt for one hour. A kilo-watt hour is a thousand watt-hours.
Waveform Distortion: Any power quality variation in the wave shape of the voltage or current.
A white paper on power problems
The availability of business systems is significantly impacted by AC mains power quality. The degree to which power quality affects business systems depends on many factors, which include:
1. The quality of the electrical power
2. The downtime caused by factors unrelated to power
3. The ability of the business systems to recover from power problems
These factors vary greatly from site to site and from business to business and therefore it is inappropriate to make general statements regarding the impact of power on business process availability. Nevertheless, it is possible to take into account the specific issues of a site and a business and determine the quantitative effect of power problems on business operation
What constitutes a power problem?
AC power is imperfect. All AC power exhibits defects almost continuously including harmonic distortion, sags, swells, RF noise etc. Common citations regarding power quality and the frequency of power problems can be highly misleading because they often include power defects that do not affect information equipment. For a meaningful discussion of the effect of power problems on information equipment, a power problem must be defined as a condition where the AC power does not meet the necessary and sufficient conditions required to provide equipment operation. The generally accepted definition of necessary and sufficient power quality is the magnitude and duration of power problems which are likely to affect information equipment.
The Electric Power Distribution System
For purposes of understanding the distribution of Electrical Power, the system is typically separated into the following four levels:
Distribution Level Equipment
Bulk Power — Power Plants
Area Power — High Voltage lines
Distribution Network — Neighborhood power lines
Utilization Equipment — Building wiring
A failure at any of these levels can lead to a failure of equipment operation at the user site.
Bulk Power is defined as a composite of the Generating Stations and the very high voltage transmission network. Problems with Bulk power affect the largest number of users. These problems are caused by
1. fuel shortages
2. human error
3. plant shutdowns
4. planned conservation
The statistics for Bulk Power availability vary widely. For example, on a small island Bulk Power may be a major contributor to down time. In Western Europe, the USA and Japan, the Bulk Power system is highly fault tolerant and a Bulk Power loss may occur only once every ten years or less.
Area Power is defined as the transformer stations and substations supplying a given area.
Problems with Area power affect large blocks of people such as entire towns or cities. These problems are caused by:
1. equipment failure/wear out
The statistics for Area Power availability vary widely. For example, some countries routinely employ interconnected stations with fail over capability while others employ a single path system. Systems with fail over capability provide a much lower mean time to repair and hence higher availability.
The Distribution Network is the local network of wiring which feeds buildings. This wiring typically follows streets and operates in the range of 5kV to 30kV and includes the transformers at the users site, which convert the power to the final utilization voltage. For many sites distribution is the primary cause of power problems. The distribution network is highly complex and exposed to many factors which can cause a power problem, including:
4. vehicular accidents
7. construction accidents
The statistics for power problems in Distribution Networks are most strongly affected by local weather. In systems where Distribution wiring is underground these affects are reduced dramatically. In some cases, a significant degree of fail over redundancy is designed into the local distribution system, which reduces mean time, to repair and therefore increases availability.
The Utilization System consists of building wiring, circuit breakers, and internal building transformers. Power problems arising in the customer’s Utilization System are mainly independent of the geographic location of the site and are caused by factors that are typically in the control of the customer, including:
2. construction accidents
3. scheduled electrical work
4. electrician errors
5. heavy equipment startup
6. poor wiring connections
The statistics for power problems in Utilization Systems are most strongly affected by the existence of construction or wiring changes in the building, the nature of the business (industrial vs. knowledge workers) and the age of the building and wiring. In situations where the quality of the power supplied by the Utility Company is high, power downtime may be dominated by Utilization System problems within the customer’s own facility.
Power protection devices
Power protection devices have traditionally fit neatly into one of two categories; those that alter, change, or otherwise control the character of electricity and those that provide an alternate or secondary source of power in the event of the failure of the primary
source. Products in the first group include surge protectors, filters, voltage regulator, power conditioners, and others. The amount of protection varies from device to device. The operational requirements of LAN systems along with an emphasis on protecting data, software, and processes have created a significant level of interest in the uninterruptible power supply (UPS) products that comprise the second group. While it is possible for a UPS to also function as a power conditioner, such capabilities cannot automatically be assumed. Indeed, along with the rapid growth in the number of UPS suppliers, the industry has seen the distinction between a UPS and a power conditioner become too poorly defined.
The best place to start is by highlighting several of the most common misconceptions concerning UPS products.
A UPS provides total power conditioning. · For total power conditioning, an on-line UPS (as opposed to a standby design) must be used.· Standby UPS systems are undesirable because they only become active when power is lost.
Much has been said and written in the battle between different UPS technologies. It’s important to recognize that today, most UPSs are used in applications where the system is powered by a switch mode power supply. These power supplies make computer systems very tolerant of both voltage variations and short duration (5-20 msec) power losses.
The fact is that systems powered by switch mode supplies (and that’s most systems today) are perfectly compatible with standby UPS designs. Equally inaccurate is the assumption that because of its inverter design, an on-line UPS provides superior power conditioning to a standby UPS.
It is true that on-line UPS systems provide excellent normal mode protection (between line and neutral). Normal mode protection, however, is only one part of the power-conditioning picture The switch mode supply is a significant improvement in electronic system design for a number of reasons. Not only does it make system more tolerant to voltage variations, but it is also smaller, lighter, more efficient, and quite a bit cheaper to produce.
All these advantages come with a price tag, however. The predecessor to the switch mode supply was the linear supply. It was characterized by a step-down isolation transformer on the input side. Elimination of the transformer in switch mode designs accounts for most of the physical and economic advantages.
However, it also results in a distinct operation disadvantage. That is the loss of common mode (neutral to ground) noise immunity for the system. Modern microprocessor system use electrical ground as a signal reference when making logic transitions and for the proper exchange of data between systems and peripherals.
For reliable operation, ultra-quiet ground reference is a necessity. Common mode disturbances disrupt this clean signal reference. Such disturbances can only be eliminated with an isolation transformer. It is important to recognize that a UPS – any UPS – should include an isolation transformer in it output circuit. Without it, the UPS cannot qualify as a power conditioner because it will not be capable of protecting the attached computer system from common mode noise.
There is a proliferation of UPS systems available in the marketplace that do not contain all the elements necessary to provide complete protection to the sensitive electronic load. This is true for both on-line as well as standby designs. Example abound of both types of UPS designs that fail to incorporate an isolation transformer as the final stage of their construction .