On our desk this week - 7

Is there some rational reason for UPS's to describe their output as being in "Volt-Amps" instead of Watts like normal people?

In Australia, our electricity bills are made out in "Kilowatt-Hours" which has always given me the irrits.

Nezuji

 

Volt-amps is easy to convert to kilowatt hours (if my memory serves correct).

P=IV = Amps x VOlts

P is in watts, so every hour it outputs 1V at 1A is 1 watt hour.

 

imo there are 3 problems with that UPS: how do you play CS without a monitor? Don't tell me you are that good with only headphones And probablywithout network or internet connection? (or do anything else)
AFAIK most new UPSs provide some sort of spike filter for mains, network and/or phone lines. And in a quality one probably it realy works
And as some1 already asked if the output voltage of that UPS is not real sine wave, it will have problems with active PFC PSUs.

I have a refurbushed 900VA APC UPS, that can run my not so up to date computer+19" CRT+amplifier+some room lights for 30+ minutes.

VA is not always equal to Watt on mains lines. But i think someone with proper english should tell the details

 

As for the spike problem, you should always have a surge protector for your computer anyway.

 

oops

 

That was kind of my point. P = VI -- Watts = Volts x Amps -- therefore, saying "Volt-Amps" is the same as saying "Watts". I was only making the reference to "Kilowatt-Hours" as an example of another daft measure. "Joules" or "Megajoules" (given the amount of energy we're talking about) would seem much more natural to me. 1 KWh = 3.6 MJ, after all.

LukR made an interesting reference to something about the influence of mains power. Something to do with AC power? RMS Voltage? I'm really interested to hear from anyone who really understands why UPS's are measured in "VA" instead of "W", and can explain it to me. In fact, wouldn't it be more rational to measure them in Joules, or even "Watt-Hours", if you wanted it to make it easy for consumers to figure how long your UPS will run their X-Watt system? I mean, "This UPS can provide 600 VA!"... Yeah? For how long?

Nezuji

 

linky about UPSs, power factor, VA and W

As for how long will it run your system: either read that article for some a bit old information, or go to the manufacturers website. APC's for example gives an estimated runtime for a given power draw link.
Set the Power Draw for the actual power consumption of your rig, not to the rated power of your PSU. Most avarage machines use about 250-350W of power with a monitor (yeah, PSUs are a bit overhyped).

 

5.1 without a doubt, get your ears pumped full of n00b carnage on CS source

 

Would you need a 500V one for a system with a 500v psu like a Antec NeoHE 500V? and how much would they cost if i would need a more powerful UPS? Also do they come with replacement facias, e.g silver or do you just have to do it yourself.

 

Thanks, LukR! I'll read it when I get home.

Nezuji