3 or 5kva inverter

It would probably be cheaper and easier to run the computer off of a battery type arrangement rather than an inverter. It would be prohibitively expensive to make a DIY inverter system. Best would be to either purchase an inverter or, if you are running a laptop you could wire it to a battery arrangement.

thanks for your help, but how can i run my 4 cpu's on batterys including the 15 inch monitors

Hello Austintik,

Try http://www.apc.com/index.cfm?isoCountryCode=ng

The link is for APC products. I notice that all the power output numbers are given as both watts and in VA. Does the difference indicate the power factor of these devices. Pretty poor if it does.

Example, one product for a small business application is rated 400 watts but also 650VA. I was looking at this company's (APC) products in the store two days ago and the largest unit was rated 800 watts but 1560 VA. The literature did say the output was MSW meaning modified sine wave. Nowhere could I find a THD value. I suspect because it was so bad the company did not want to publicize it.

Secondly, Most small UPS do not produce clean sinewave output. Users of laptops with "universal" voltage chargers should be aware that many of these so called universal power supply or battery chargres are not happy with MSW. I have seen numerous instances of these power supplies burning up. In the case of small inverters of 300 watt rating the inverters are also damaged on occasion. These comments are based on my experience as an application engineer with an inverter manufacturer.

Desk top computers with switch mode power supplies are more tolerant. However this past year I have seen a few of the newest ultra fast computers shut down when I attempted to power them from an MSW inverter source like you get in these smal lUPS. The dealer Tech informed me the new power supplies are sensitive to power quality and rejeft poor power factor supplies wit hhigh THD content.

Elnav,

The Ratings on the APC gear are to Allow for poor PF on the equipment being supported. They support .95Lead to .8Lag.

So if the PF on the load is closer to unity you will actually get more value from the UPS.

As a side note, many PCs & Servers actually run at a Leading PF due to the Switched Mode power supplies...If the PF is leading to much, the smaller UPS will go out on Overload and you wont be able to work out why without a CRO or Smart Meter.

It is causing all sorts of havoc in Data Centres especially since Generators don't like Leading PF.

Regards,
Sapper

Thanks Sapper. From what you say a 840 watt / 1500VA APC unit would support close to 1500 watts of load provided the load was power factor corrected. The store staff was unable to explain or even understand the spec sheet of the products they were selling. I didn't know if this was simply some marketing hype or a legit spec. regards

Elnav

Wrong store eh?

You may not be familiar with power supply issues or the various methods used least of all the best "clean power" method; strip to basic DC properties then transform to clean AC. Rectifier bridge

Suggest contact professional audio technician, electrician, electrical supply or PRO A/V technical consultant. www.sweetwater.com, www.musiciansfriend.com , www.adkproaudio.com , google furman, APC, Monster cable, sola hevy-duty, etc..

Modified sine wave is great, is consistent marvelous. Yes it is square, why? Is it analog? Does it matter. What are the differences if your municipal power supply is derived of hydro, fuel burning or wind? Which causes harmonic distortions and what is effected most by that distortion? What is the average # of power sags per day in the USA? 5-6 figures, locally; any locality about 700-3000 per/day.

I use APC almost exclusively primarily to filter electrical noise and protect A/V equipment from power sags.

The market place has room for several vendors but some of offerings are better suited to specific tasks and APC covers this open field better than many.

In post #2 I gave a link to APC-Nigeria because the poster resides there.

Can You import

From China-- I can link you

Solar Panels+Battery charger+ Inverter(as another friend said-you can operate direct from Battery)

Drawing 3-5kVA out of 12V makes no sense because the current will be >250A...400A and the copper/semiconductor losses would kill the efficiency of such a system.

Inverters of such size need remarkable higher primary voltages of, lets say, minimum 96V (which would be available from 4 x 24V truck batteries), better 200-300V.
But, as others posted before, why not run the single computers with solar power and car batteries ?

You might look at inverters for marine applications. There are any number of pieces of equipment available for vessels that fulfil this requirement, and you might get one off the shelf.

A Xantrex 3.6k with 6 6v. batteryes will handle all your needs.

Just thought I'd let everyone know that I've found some nice 12 volt portable jumpstart systems with built in air compressors. I haven't personally bought one yet. I'm a shopper and a traveler, I think they are perfectly priced for savings! These guys actually have tons of killer 12 volt products. Stuff like a 12 volt power supply for at home use and 12 volt flat panel televisions.

Happy Shopping Folks,
Steve - Truckin'

... but does not just sound like 3 ... 5 kVA - equipment ...

Sigh! - one born every minute.

I used to work for the company that makes them. The inverter is 300 - 500 watts not 3 - 5 kW Inside there is a 20 amp hour battery AGM type. At full load it doesn't last long.

The original query was from Nigeria. Unless I miss my guess they are 220V 50Hz utility power and inverters should be similar.

Victron is one of the few products that is switch selectable for output frequency. Which is why I use them fo rboth my US and European system designs. Their products can be paralled up to 15kW per phase and can handle being wired either as single phase or three phase. The requisite synchronization is already built in.