[Discuss] UPSes - A Question....

[R. McFarlane]

On 12/14/06 1:05 PM, Adam Parkin wrote:

> Okay, a question for those who are more knowledgable than myself (I am a 
> computer scientist, not an electician after all) =;->
> 
> Would the above APC be adequate for my needs which consist of handling 
> power to the following gear:
> 
> - a P2 350MHz using (I believe) a 200W power supply
> - a P4 3GHz using a 450W power supply
> - a 21" CRT Viewsonic monitor (I don't have a manual for it, but the 
> specs on the viewsonic site state:  "POWER Voltage AC 90-264V, 50-60Hz, 
> Consumption 115W")
> 
> All I want the APC for is to avoid having my computer reboot when the 
> power blips (which has happened twice in the past week with this crazy 
> wind), and in the event of a power outage give me enough time to do a 
> proper shutdown (I'm fine with having to shut it down myself as actually 
> my desktop machines aren't usually on while I'm out).

<snip>


	Based on the gear you indicate, you have a maximum draw of 765 watts. 
The 21" CRT will be the biggest user of power in spite of what it says 
on the power consumption. Laser printers and CRT displays are devices 
typically not plugged into an UPS.
	Based on my experience, knowledge and what you have referenced above, I 
would recommend a 1000VA UPS minimum. That being said, the 21" CRT will 
drain a UPS of that level FAST. You will get longer battery life if you 
sell the CRT and get an LCD instead.

	To put this into perspective, my first UPS was a Belkin 500VA. It 
"claimed" that it could support a 17" CRT. The reality was that when the 
UPS was on battery and the CRT was on, the UPS overload alarm would go 
off and if I left the CRT on, I would get less than 5 minutes of up time 
but in all actuality the UPS would turn off to protect itself due to the 
overload state brought on by the 17" CRT.

	I highly recommend upgrading to an LCD and then you may be safe with a 
700VA UPS.
	A relatively "safe rule of thumb" is to take your total wattage and 
double that for a VA rating. This is not the correct way, but this is a 
quick/easy way.

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