UPS Runtime Calculator

Announcements No Responses »
Feb 162012

Following on from a previous post regarding misleading UPS specifications, we’ve put together the UPS Runtime Calculator which you can use to check the runtime for a variety of battery configurations on many different UPS types.

UPS Runtime Calculator

UPS runtime is mostly determined by the load and the battery. Higher capacity UPS need not necessarily give longer runtime for the same load. For example a 1500W UPS like the KR1500J contains an attached battery containing 8x9Ah batteries. For a load of 1000W this will give 20 minutes of runtime. The E203R however, is a 2400W UPS, but contains 6x7Ah batteries giving a runtime of 10 minutes.

Generally speaking for these professional UPS, manufacturers and dealers tend to be more accurate with the runtime figures. It’s at the budget end of the market where runtime information becomes a little bit vague.

I’ve seen adverts for 600VA UPS giving 45 minutes runtime, yet the unit contains only 1x7Ah battery. At a load of 300W, the runtime would be only 4 minutes. To get anywhere need 45 minutes, the attached load would have to be under about 50W.

The UPS Runtime Calculator can be used on for any UPS containing 7Ah, 9Ah or 12Ah or equivalent batteries. You need to know the number in the UPS, enter the load and hit Calculate. The estimated runtime will be displayed.

For the Power Inspired range of products, you can simply select the product of interest, enter the load and the runtime will be calculated.

Posted by toneus at 7:16 pm Tagged with: , , ,

Outage in Oxford leaves 100,000 Properties without Power

News No Responses »
Feb 142012

In the office today at lunchtime and just made a cup of tea. Just as well as a few minutes later the lights went off and the sound of our UPS system maintaining the computers and phone systems started alarming.

First thing was to check our distribution board to make sure an internal fault hadn’t tripped our own breakers – it’s happened before with burnt bread in the toaster and a water leak onto the power sockets to name just two occasions, but no, this time our breakers were all on, and so the fault was external.

Of course we were safe in the knowledge that all our systems were still up and running, with the exception of the kettle, but then, providing UPS support to enable tea making during a power cut does seem a little over the top. And in any case, I had mine.

A few minutes elapsed and hey presto, the power was restored, the UPS’ stopped alarming and everybody else was able to make a cup of tea just in case the power went off again.

Southern Electric say this outage was caused by safety devices operating that took down a high voltage network. Although not specific in the causes, a cable fault was to blame and that this looks like it was caused by vandalism. In fact probably dug up by some criminals fully aware of the price that copper fetches these days and just a symptom of this ever growing criminal activity. As a result, such occurrences are bound to be on the increase, causing more and more disruptions to the electricity supply.

It doesn’t cost that much to protect your systems and we have a range to suit all applications and budget. Our VIX2060 is only £36, and provides battery backup for a home office PC and is provided with USB interface and software to shut down the system gracefully ensuring that your data is preserved. Larger capacity 1200 and 1500VA models are also available for higher powered systems or for longer runtime.

For more advanced power protection or longer runtime requirements, the KR online double conversion UPS Systems provides the highest level of power protection with expandable runtime. And of course, if you’re looking for the highest degrees of power protection but cannot suffer the noise of online UPS, then opt for the AG series of AC Power ReGenerators.

Reported on BBC http://www.bbc.co.uk/news/uk-england-oxfordshire-17029807

Posted by toneus at 6:10 pm Tagged with: , , ,

AC Power ReGenerator FAQ

Help Guides, Product News No Responses »
Feb 142012

Here’s a list of some Frequently Asked Questions and some not-so frequently asked but useful knowledge about the AG series of AC Power ReGenerator.

Q. Will I see an improvement in sound or picture quality?

A. Maybe, or maybe not. If your power quality is poor then the AG series will no doubt provide an improvement. If you have a pretty robust electrical supply then you probably won’t hear or see any difference. We’ve had feedback from users that the AG series provides an enormous improvement in sound quality, however these reviews are of course subjective. We don’t make any claims that performance will be enhanced, but the AG series will protect your investment from power disturbances and will not cause any detrimental effects.

Q. My mains voltage is high, what can the AC Power ReGenerator do about that?

A. The output of the AG series is fixed at 230V to within a volt or two. You will never get anything higher or lower than this regardless of what the input power is doing. There’s no need to sit watching a multimeter afraid of high voltage causing damage to your system. The AG series never passes damaging high voltage through to your load – ever.

Q. My mains supply is good, why should I need an AC Power ReGenerator?

A. Your mains supply may be good at this moment, but there are so many external effects influencing power quality that there’s no way of predicting if your mains supply will be good next month, next week or even in the next hour. The AC Power Regenerator removes all these uncertainties and provides a constant clean source of power.

Q. Does the AG series provide any other features such as the ability to demagnetise transformers etc.?

A. Err, these are gimmicks. Some of these products also produce square wave power sources and claim these are better for some applications.  Square Wave inverter circuits are cheap and in our opinion only suitable for providing momentary power ride through or enough to provide an orderly shut down of a computer. In fact a square wave power source is full of power viruses. We would never condone using a square wave on any sensitive apparatus. The AG series provides a high quality 230V 50Hz power waveform, end of story.

Q. Is the AG series noisy?

A. Not at all. The AG500 has an audible noise level of under 15dBA (alarms excluded) and is hardly noticeable. The AG1500 at full fan speed is around 25dBA, which is quiet but may cause a distraction in certain applications. However, if the your load will only run at full capacity for a few minutes, the fan speed can be turned down. At minimum speed the AG1500 is super quiet at around 10dBA and you can run the system at around 40% load continuously – that’s around 600W.

Q. How big and heavy is the AG series?

A. The AG500 is a single box solution containing internal batteries and weighing in at around 15Kg. The AG1500 is a two box solution with the batteries housed in a separate matching battery enclosure. The AG1500 weighs in at 11kg and the battery box 28Kg. The size of the enclosures is 88x440x440 and occupies 2U of rack space. Check out the AG Series Specifications. The units can be mounted in a 19″ rack, horizontally, or placed vertically upright, so physical arrangements are very versatile.

Q. I don’t want or need battery backup, can I still use the AG series?

A. The AG1500 will work without attached batteries and will act as a pure power conditioner. A battery warning light will flash on the front LED display but that is it. Of course in the event of a power cut the unit will simply switch off.

Q. What happens in the event of a fault?

A. Some systems will, in the event of a fault or even during power on, go into what is called “bypass mode” and provide raw mains power straight through to your load. We believe that the purpose of the AG series is to ensure that raw mains power never gets through to your load, which is why this bypass line is disabled by default. Where power conditioning is less important than power continuity, the bypass line can be enabled but this is a factory setting option. If the AG series suffers a fault, such as overload, over-temperature or failure then the output will be shut off.

Posted by toneus at 11:21 am Tagged with: ,

AC ReGeneration Article#5: The Solution

Applications, Technology No Responses »
Feb 102012

 

So far we have discussed how electricity is produced, transmitted and corrupted on it’s way to your power outlet. We’ve described how power viruses are created and how impedance and harmonics have a negative effect on equipment performance. So what can be done about it?

AG Series AC ReGenerator

AG Series AC ReGenerator

Certain power protection solutions are available for particular power problems. Surge Protection is one such example. Filters are another example to protect against transients and electrical noise. However each one of these solutions only works for a particular problem. Indeed there are certain problems that cannot be cured with a passive component.

This is where the principle of AC ReGenerator solves all power quality issues by recreating a new high quality sine-wave power waveform from a low impedance source capable of delivering instantaneous peak current for maximum equipment performance.

The AG Series of AC ReGenerator delivers superb power protection performance, and what’s more does it without causing undue distraction in terms of audible noise. This makes it suitable for use where previous online technologies fail.

Let’s recap the power viruses and how the AG series protects against them:

Virus AC ReGenerator Performance
Power Cut Units either contain (AG500) or have external (AG1500) batteries in order to provide power during an outage
Voltage Fluctuations The output of the AC ReGenerator is fixed at 230V. This is stable and unchanging regardless of the input power level.
Voltage Surges / Spikes / Transients The input mains is initially fed into a filter that protects against surges and spikes. Since the output power is recreated and independent of the input none of these disturbances can propagate to the load.
Harmonics As the power waveform is created using advanced Digital Signal Processing algorithms which can make adjustments to the output power many thousands of times per second, the result is a very pure power waveform, free from harmonic distortion – regardless of the input power waveform.
Impedance The power is delivered by switching fast acting low impedance transistors. Coupled with capacitive storage the AG series is capable of delivering instantaneous bursts of peak power without any detriment to the power waveform resulting in significant performance benefits.

The AG500 500W AC ReGenerator is available now from the UPSMart webstore.

Posted by toneus at 2:22 pm Tagged with: ,

AC ReGeneration Article#4: Harmonics

Uncategorized No Responses »
Feb 062012

When electricity is generated at the power station, the resultant voltage waveform that is produced is generally a very high quality sine wave. Loading on the supply network particularly by non-linear types of load such as variable speed drives, rectifiers, computer power supplies, fluorescent lighting etc., cause a distortion to this waveform.

The distorted waveform can be analysed using a process called “Fourier Analysis”. Now this is quite complex maths, which we don’t need to go into, but what Fourier Analysis tells us is that the resultant waveform is actually a pure sine wave waveform called the “fundamental” with “harmonics” added to it. A harmonic is simply another pure sine wave of a frequency that is an exact multiple of the fundamental frequency. For example, for a 50Hz waveform, the 2nd harmonic would be 100Hz, the third 150Hz etc.

The diagram above shows how the addition of harmonics changes the pure sine wave into a square wave. Now the question is how does this happen? Well let’s take a look at the following diagram:

How non linear current demand causes sine wave distortion

Sudden demands of current cause waveform distortion

 

 

A rectifier takes current in spikes as can be seen in the red line above. Now remember what we said about impedance? If the impedance on the supply is high, these peaks of current will cause an instantaneous drop in the voltage (remember Ohms Law), which will rise up again after the current demand has subsided. This instant voltage drop and rise causes distortion to the supply waveform. It will always happen on any supply line but is unnoticeable on low impedance sources as the amount of distortion is directly proportional to the supply impedance (Ohms Law again).

The amount of distortion is measured using a quantity called “Total Harmonic Distortion” or THD for short. It’s actually a ratio of the total power of all harmonics to the power of the fundamental and expressed as a percentage. So it follows that if there are no harmonics present then the THD will be zero and the more harmonic content that is present, the higher the THD. According to international standards the limit for a power waveform to no longer to be considered sine-wave is 8% THD.

So what? Well harmonics can cause some severe power quality problems including fires in certain circumstances. For the regular user though harmonics cause equipment degradation, loss of performance, unwanted audible hum and noise, mis-operation of equipment etc.

 

Posted by toneus at 6:27 pm

AC ReGeneration Article#3: Impedance

Applications No Responses »
Feb 042012

Impedance is the obstruction or opposition to the passage of flow of, in this case, electricity. Many of you would have heard of Ohms law, and probably know the famous equation V = I R and so are familiar with resistance. Resistance and Impedance are not the same thing.

Resistance is fixed regardless of the frequency of the applied voltage. Impedance is not and varies depending upon the frequency of the applied voltage. Not only that, but since an AC source is constantly changing, the current that flows due can be “out of phase” with the voltage waveform.

Inductance and Capacitance in an AC source add “reactance”, and this coupled with the “resistance” give a measure of the impedance of an AC source, which as well as the current phase shift becomes relatively complex to express simply.

We can do some simple maths, but if that’s not your thing then don’t worry, just skip over and look at the results. Assume we have an AC source with a resistance of 1 ohm. If our connected load takes 10Amps of current then, according to Ohms law V= I R we have a voltage reduction of 10 x 1  = 10Volts. When current is zero then this voltage reduction is zero, so for a 230V source if you were to measure with no load you would read 230V and if you were to measure with 10A load you would read 230V – 10V = 220V.

This explains why the voltage can rise up and down when heavy loads are switched on and off in a circuit.

Now we just mentioned resistance above, with no mention of impedance which is what this article is about. When we add impedance the situation becomes a little (OK a lot) more complicated. As we mentioned above, impedance is frequency dependant. For capacitive circuits the impedance reduces as frequency increases and for inductive circuits the impedance increases as frequency increases. For a mixture of inductance and capacitance in a circuit we can get sweet spots which is the basis of filter design, but this is not what we are interested in here.

What we are interested in, is how can impedance affect our equipment performance. Well, what is true for voltage is also true for current, and instantaneous demands of current cannot be met with an AC source that has high impedance, especially inductive impedance.

A high grade amplifier for example, will demand peaks of power in order to deliver the best performance. These peaks manifest themselves as instantaneous high current demand on the source. This is analogous to a high frequency current demand and, as we now know, impedance changes with frequency. For an AC source with a high inductive impedance it will not be possible to deliver the required instantaneous current, resulting in reduced performance.

Impedance is unavoidable except in the world of super conductors, but can be minimised. Some people may already be lucky enough to have a low impedance source and get optimum equipment performance, but for many the effects of impedance cause a reduction in performance that may not be at first noticeable until you compare with operating the same system with a low impedance source.

Impedance is not considered a power virus in itself, but it can cause power viruses, voltage fluctuations in particular, but also, as discussed here, performance issues that are generally unexplained or unknown.

Posted by toneus at 8:54 pm Tagged with: , ,
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