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BazC
01-11-2007, 03:40 AM
Not graphics related I'm afraid but I hope someone can help anyway!

I've been using a Belkin Uninterrupted Power Supply with my eMac for a few years and it's worked flawlessly. Now I've upgraded to a Mac Pro (2.66) and the UPS isn't powerful enough. When the Mac is working hard, rendering for instance I get an overload alarm from the UPS and the one time I suffered a powercut on the Mac Pro it shut down instantly, the UPS did no good at all.

So I have to get a bigger one. The problem is figuring out which unit will do the job. The only power supply info I can find on the Mac is that it needs 6amps (high voltage) or 12 amps (low voltage) I'm in the UK where the mains is 240volts.

The only advice I can find on choosing a UPS says multiply the amps by volts to get a va rating and choose a UPS a bit higher than that.

Well if I multiply my Mac pro High voltage rating of 6 amps by mains voltage I get 1440va Most Belkin units are in the 425 to 625va range! Their biggest unit seems to be 1200va! Does my Mac Pro need something even bigger!?

I'm not having much luck getting advice from Belkin can anyone here help or suggest where I go for info?

I'm using the Mac Pro with a 20" LCD

Cheers - Baz

BazC
01-11-2007, 03:52 AM
http://docs.info.apple.com/article.html?artnum=304387

I've just found info on Apple's site that says the 2.66 Mac Pro draws a maximum of 250W which seems much more reasonable! It doesn't help much in choosing a UPS though as Belkin rate all their units in va, I thought that was the same as watts but apparently not :(

BazC
01-11-2007, 04:17 AM
OK I've found some more advice so I think I can figure things out now.

A discussion on the Apple forums suggests getting a unit with minimum of 800va, another post says 500w should be more than enough.

http://discussions.apple.com/thread.jspa?messageID=3039674&#3039674

LW_Will
01-11-2007, 10:20 AM
V=A*W

W=A/V

;-)

LW_Will... who took lighting in Film school...

BazC
01-11-2007, 10:34 AM
V=A*W

W=A/V

;-)


Errr nope, Watts = amps x volts which is what I though va was too (volt amps) apparently not though.

http://en.wikipedia.org/wiki/Watt

I just found this (http://en.wikipedia.org/wiki/Volt-ampere) explanation on Wikipedia

___mats___
01-11-2007, 11:06 AM
Baz -

I dont know about voltage and formulas, or if the 220v in the UK affect the UPS rating,

but just so you know Im using a 1200v APC UPS on a quad G5 (which consumes more thant he intel macpro) and a 30'' display and printer, router, cable modem and audio system on it and the "overload" light never blinked, so something like that should hold up pretty well, I didnt do much research on the voltage and consumption (I probably should have) I just tried to go with the highest voltage ones just to be safe (these UPS paid for itself after the storm and power surges we had in the PNW area)

Good luck !

BazC
01-11-2007, 12:10 PM
Thanks Matt, I've just ordered a 800va unit from Belkin which should hopefully be up to the job. It should be delivered tomorrow so I'll post how I get on.

Cheers - Baz