FAQ´s
UPS Releted FAQ´s
- What is a UPS?
- UPS is a power supply system with energy storage which ensures a permanent supply of the load in case of a supply voltage breakdown
- What is the difference between "KVA rating" and "KW rating" of UPS?
- The mathematical relation is kW= kVA *pf. where kW is active or useful power and kVA is the vector sum of active power and reactive power. The equation therefore is kW= kVA *pf
- What is the Input Power Factor (p.f.) of the UPS at different loads?
- Power factor is a function of phase displacement angle between voltage and current and distortion factor. It is calculated as a ratio of real power to apparent Power drawn by load. PF is low at lower loads and goes on improving at higher loads. PF is also lower at higher input voltage and goes on improving as voltage reduces. Input Power Factor is independent of type of load for double conversion technology
- How much is the static switch transfer time (Break in output) in Asynchronous and Synchronous mode if inverter fails?
- In synchronous mode this break is less than 5 ms because of Static Switch in output and Inverter is in phase and frequency locked with Bypass. In case of Asynchronous mode it is between 15-20 ms.
- What are the types of load applied to UPS during testing?
- Resistive load and non linear load for normal testing and Inductive load on special request of inspection authority
- What happens if UPS fans fail?
- Fans are provided for cooling of wire wound components as well as cooling of heat sinks. If these fans fail, internal temperature of the unit will increase and when the heat sinks temperature rises above 850 degrees Celcius it will give indication of 'Over Temperature'. If this condition persists, Inverter will be switched off after 3 Minutes.
- Is UPS output isolated from its input?
- Yes, double wound isolation transformer of full load UPS rating is used at inverter output, which ensures complete isolation from input.
- Can the UPS output neutral be earthed?
- Yes, provided bypass isolation transformer is used or the operation of static switch is permanently disabled.
- How to monitor an UPS in network?
- SNMP Card along with Software can be used to monitor UPS in network
- What are advantages of Isolation?
Isolation ensures all impurities at supply input are filtered & not allowed to reach load.
Inverter Releted FAQs
- What is an inverter?
- An inverter takes DC power (battery or solar, for example) and converts it into AC "household" power for running electronic equipment and appliances.
- Why are they called inverters?
- Originally converters were large rotating electromechanical devices. Essentially they combined a synchronous ac motor with a commutator so that the commutator reversed its connections to the ac line exactly twice per cycle. The results is ac-in dc-out. If you invert the connections to a converter you put dc in and get ac out. Hence an inverter is an inverted converter. For more information about such converters see.
- How can an inverter be used?
- With a large enough battery bank, almost anything within reason can be operated from a power inverter – this assumes that the inverter has the proper power output for the given load. Everyday appliances such as microwaves, power tools, TVs and VCDs, lights, audio/visual equipment, battery chargers, tube lights ,Fans and computers are common loads. An inverter sized for loads with heavy inrush current can be used to power air compressors, water pumps, heaters, ventilation fans, and air conditioners Kevin Pure Sine Wave inverters\Home UPS are ideal for running sensitive test equipment such as communications equipment, oscilloscopes, scales, high end stereos & video equipment, communications equipment, etc
- What is Sine wave ?
- It is the ideal waveform for the transfer of AC power. There are two types of waveforms available. A "modified sine wave", and the "true sine wave".
Modified Sine Wave -The modified sine wave is not really a sine wave at all. It is more less a "stepped wave". It achieves voltage regulation by varying in width according to the battery voltage and the load. Thus, the wave is not as smooth as a sine wave. The quality of modified sine wave inverters should not be underestimated. They are highly capable, and (by narrowing the waveform) they save energy when running only small loads, as happens during most of the day in a typical home. Modified sine inverters have been successful in many thousands of remote home, RV and marine systems since 1986.
True Sine Wave - Also known as Pure Sine Wave, is the most reliable waveform and provides power almost identical to a standard wall outlet. The power produced fully assures that your "sensitive loads" will be correctly powered, with no interference. Some appliances are likely to require Pure Sine Wave including digital clocks, battery chargers, light dimmers, variable speed motors, and audio/visual equipment. For these reasons, true sine wave inverters can be more a more expensive choice.
- Why do I hear buzzing on my stereo when using a modified sine wave inverter?
- Some inexpensive stereos use power supplies that cannot eliminate common-mode noise. These would require a sine wave inverter to operate noise-free.
- How do I know which inverter to buy?
- Different devices require specific wattages to run correctly and efficiently. Please use this easy formula to determine the correct size inverter:
AMPS x 220 = Watts
Example: 10 Amp Unit X 220 = 2200 Watts
- What is the Low Voltage Alarm & Shutdown?
- The low voltage alarm will sound when the DC source falls below 10 Present and the automatic shutdown will power off the inverter. This is done to save your battery(ies) so you can restart your vehicle.
- Is my inverter weatherproof?
- No. Treat your inverter like you would your TV. You wouldn't put your TV outside in the rain, please don't leave your inverter there either. Be aware of lighting storms. If struck, your inverter would go into a permanent overload state and may even smoke it. If using in a marine environment, try to keep it tucked away underneath, in a dryer area.
- How do I charge the battery for my inverter?
- Because inverters operate from a DC (Direct Current) power source, usually a battery bank (one or more batteries), the battery source will have to be recharged at some point. (Remember that a battery discharged more than 80% is probably close to being dead.) Depending on the inverter load and runtime required, most power applications will be covered by the charged battery. If the load is large (air conditioner, large draw power tools, large microwave, food freezer, ice cream machine, etc.), the user should verify that the installed inverter is of large enough capacity to operate this power requirement.
- Battery installation tips.
- Connect high amperage accessories such as a winch to the top terminals only. Do NOT use the side terminals.
- Replace any cables and connectors that have corrosion, rust, or other damage.
- Do not install batteries in a non-ventilated or sealed compartment.
- Do not lift or handle the batteries by the terminals.
- Do not over tighten terminal bolts.
Battery Mgmt Software Releted FAQs
- Why should I monitor my batteries? I already have a quarterly maintenance contract with my UPS or Battery Service Provider.
- Your quarterly maintenance contract is not adequately protecting you. Batteries are inherently unpredictable and can fail in as little as two weeks, at any time in their life cycle. Monitoring protects your investment and your profits by making sure failures do not occur between service intervals.
- How does Battery Monitoring help me?
- For the first time, you can detect impending battery failures before your backup system is affected! You will know in advance which batteries should be replaced and have the time to act accordingly.
- How Does Battery Monitoring Work?
- The technique is actually very simple! ENERTECH places a sensing wiring harness over each of your batteries. Over this harness, we measure each individual battery cell voltage, impedance and temperature, plus current and voltage during a discharge. The data is stored in the monitoring system controller and analyzed with ENERTECH's software. The system can alert you of alarm conditions via e-mail, cell phone text message or your facility management system. By trending of the battery cell impedance from the baseline measurement when it was new, it is possible to correlate the impedance rise with the end of its service life.
- Doesn't my UPS or battery charger already monitor my batteries?
- Your UPS or Charger cannot detect developing problems - your UPS system is at risk long before its alarms are tripped. UPS systems only monitor conditions on the whole battery bus, not individual battery health, and cannot detect failures in advance.
- Doesn't your system just add to my costs?
- The battery monitoring system will reduce costs and save money. If the ENERTECH system eliminates just one battery system failure; you will save many thousands of dollars in potential lost revenue, data and productivity. The ENERTECH system will also allow you to prevent or reduce un-planned emergency visits, unnecessary testing (disruptive load bank testing etc.) and extra maintenance visits.
- Why should I install a Monitoring System if we can buy new batteries for just a small amount more?
- Up to 3% of batteries fail during the warranty period, and you need some way to pick out the weak cells quickly before they affect your new system. Installing a new battery system does not reduce the risk of battery failure. A warranty is not the same as a performance guarantee.
- Do you have any standard measurement data that can compare with S5's impedance data?
- No, we do not have any independent measurement data on battery impedance. But what we have done is to verify our readings to several shunts of known resistance. The shunt value is known and we take a reading of the battery impedance and then we add the known shunt resistance in series with the battery. We then know that if our readings are correct the impedance should increase exactly by the known value of the shunt. We have verified this and by this method are within 0.5% accurate. Additionally, our measurements have been verified to be accurate with hand-held devices.
- What is the accuracy of measurements of impedance, voltage, and current of the battery?
- The impedance accuracy is +/- 0.5% of full-scale impedance. (Full-scale impedance is a function of the load plate current that is used for a particular installation). The voltage accuracy is +/- 0.02 volts from 1 to 15 volts. The current accuracy is dependent on the type of sensor being used. The shunt will give +/- 0.2% of full-scale accuracy and the C.T. will be +/-2% of full-scale accuracy.
- Where does the criterion come from that a battery is gone dead when the internal impedance of a battery is over 120% of the initial impedance?
- The assumption is made that the behavior of any battery that has a high impedance value is unpredictable. If you look at the graphs in the "Complete Guide" you can see that in general, once a battery's impedance starts to rise, it keeps rising until some point at which the battery could fail open. Because batteries have many failure modes and their failure points are determined somewhat by the load placed on them, it is impossible to state exactly at which point the battery has "gone dead".
- If we don't have initial impedance data of batteries (often, manufacturers do not release the initial impedance), is there any means to calculate or test the initial impedance data?
- There is no way to calculate the initial impedance values. The way to start in this case is to measure the initial impedance from the actual batteries and use this is the baseline measurement. The monitor can be commanded to perform a set of impedance measurements when the battery is newly installed which will then be stored in memory as the initial impedance measurements.
- How long should it take me to review the data?
- It will take approx. 10 to 15 minutes per week per Battery Monitoring System to analyze and review the collected data.
- Each time I look at the voltage data from a unit it has significantly changed. Why?
- Put a meter on that unit and observe the readings. The unit may be so bad that it is floating along with the bus. On a 12vdc unit, it can change by up to 5vdc and, as a result, the reported vdc can look a lot different from read to read.
- Can the Battery Monitoring System fix bad batteries?
- No, it will only indicate units that may need to be replaced in advance of them failing.
- How often should the Battery Monitoring System be programmed to collect data?
- The default standard is once per week for unit voltage and impedance, which is sufficient to prevent problems, although the system can be set to perform this reading daily. Temperature, bus voltage, discharge current and power supply to BVS® are monitored 24/7.
