Choosing the correct ups.

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blue-eye-boy

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At work we need a new ups. I would like tn get one and run all through it. But how do I calculate how big it must be? We have 3 pcs, and 2 printers. Or isnt it possible to do this? And also what brand is good? Thanks
 
Are you really hard-pressed for printing in the 20mins you'll have before your UPS battery runs out? The surge currents on printers aren't good for UPS batteries either and the load will cause a big price difference vs. only covering your pc's.
 
The P.C's are straight forward, but the printers will be the problem. If they are laser printers you either cannot connect them to the UPS or you have to get a much more powerful unit.
I have witnessed a HP Lazer blow a 1500 VA APC ups.
When you start the print there is a big power spike, and that can ruin an ups.
For 3 P.C’s a 1500 VA UPS should be sufficient to save all your work, and to shut them down.
I am a fan a buying a smaller UPS per P.C. You can get 650 VA units for about R 500 (for a cheap, but OK unit). When you start to look at APC UPS’s then the price might double or even triple.
 
Provide the specifications for the 3 computers (including PSU used, not just power, provide PSU name, model and rating) and I'll give you the calculations and recommendation, including the screens you wish to power (brand, name and model will suffice) Also if you *must* have the laser printer, post the laser printer brand, name, which model, etc. And if possible it's power specifications.

I don't really agree with Kroks 100% there, a 1500VA unit can usually supply ~1000w which *may* be enough for 3 computers, that however depends on the specs of said computers.
 
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+1 to what Gnome said.

It also depends on how long you want the UPS to run the PC's.

You'll have to post the specs of the PC's if you want us to give you an estimate of what UPS to get.
Also remember to include the screen model numbers and computer power supply model numbers too if possible.

I'm not sure if it's worth it to buy a bigger UPS just to be able to power the laser printer though. At our office we're running pretty much all our electronic equipment via an UPS, except for the kitchen stuff and the printers.

Typically an LCD screen would use about 50W and a Core i3 with an entry level/onboard graphics card would use up to about 150W.
The problem is that if you have a poor PSU for the PC, then the PC would draw/require considerably more power from the AC input due to poor/no power factor correction and a poor efficiency!
Cheap power supplies will have like an efficiency of 70%, so you should take 150W / 0.7 =~ 215W from AC input.

At my office we actually tested how much each screen and PC drew from the AC Input using an Energy Monitor device and then spec'd the UPS accordingly.
 
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thanks guys. Wil get the specs tomorow morning. I suppose its not necesary te run the printers. Why i wanted the printers to run too, is of so many orders that must be invoiced before it can go out. The one is a laser and the other a ink type multifunction fax printer. If the fax printer take less power, maybe if i can just hook that one up? Thks
 
Yeah, you should be able to hook up the InkJet printer, but the Laser one would be a problem!
 
Okay here it is:
1. PC - screen 19" takes 1.5 A
psu is a 450w
250sata hdd
onboard graphics

2. screen LG 22" takes 1.2A
http://www.pcmall.co.za/Product.aspx?SKU=P1.TQD7Z.07Z
psu 450w
onboard graphics
320gig hdd
There will be 2 of the above pc in a month's time.

3. Brother MFC 5860 cn inkjet fax/printer - takes 0.32 A

As I said, if not possible for the brother to be on then ups, then its fine, but it would be better if it was. Please just explain to me as well how to calculate the size ups I need, because we have one small ups in the office now, but we want to use it for 4 tills and 4 visa machines, because when the power fails, we hook up a generator. So the ups is just to power the tills for that 10 minutes or so. The tills takes 200mA each, and I cannot see on the visa machines how much it takes, but I dont think thats much. The small ups we have now, the output is 360W max.

Thanks.
 
my apologies if I am intruding on the op's thread, but as it is exactly what I am looking for I didn't want to create new thread.

also looking for a UPS to power the following:
i5 750
ATI 5850
2x 1.5TB, 1x 1TB, 1x 60G SSD
1x Optical
Corsair HX750W
24" Samsung

was eye'ing THIS
 
jacqvt, we run everything off a SURT5000XLI (5000 kVA, 3500 W) and it's too big. "Everything" includes 6 office PCs, 4 laser printers (not all running at once), 2 dot-matrix printers, network switch, modem, router etc, ISDN CPE, POTS switchboard, laser fax, copier, alarm, lights, etc.

We don't care what it cost, because it'll always be lower than paying staff for sitting around, talking ****. Maybe go for the SURT3000XLI (3000 kVA, 2100 W). I find that calculations tend to overestimate the load, that's why I just follow my gut.

Off-The-Chart said:
my apologies if I am intruding on the op's thread, but as it is exactly what I am looking for I didn't want to create new thread.

also looking for a UPS to power the following:
i5 750
ATI 5850
2x 1.5TB, 1x 1TB, 1x 60G SSD
1x Optical
Corsair HX750W
24" Samsung

was eye'ing THIS
Click to expand...

There are power consumption calculators online (not the APC one, that sizes your UPS once you already know what you power consumption is); there was a link to one in a thread once, but I can't find it. Just google it.
 
When it comes to UPS's, the bigger the better.
The cheap 650Va ups is only good for power dips and 5min to shutdown the pc.
That would be the only reason to put a ups on a printer. If the power goes, shutdown everything.

If you still want to work with the power off, look at laptops.
or go very big ups (5Kva+) & generator
 
jacqvt said:
Okay here it is:
1. PC - screen 19" takes 1.5 A
psu is a 450w
250sata hdd
onboard graphics

2. screen LG 22" takes 1.2A
http://www.pcmall.co.za/Product.aspx?SKU=P1.TQD7Z.07Z
psu 450w
onboard graphics
320gig hdd
There will be 2 of the above pc in a month's time.

3. Brother MFC 5860 cn inkjet fax/printer - takes 0.32 A

As I said, if not possible for the brother to be on then ups, then its fine, but it would be better if it was. Please just explain to me as well how to calculate the size ups I need, because we have one small ups in the office now, but we want to use it for 4 tills and 4 visa machines, because when the power fails, we hook up a generator. So the ups is just to power the tills for that 10 minutes or so. The tills takes 200mA each, and I cannot see on the visa machines how much it takes, but I dont think thats much. The small ups we have now, the output is 360W max.

Thanks.
Click to expand...
Ok well the specs you provided are a bit vague on the details. Also 1.5A isn't enough :) 1.5 amps is the current but at what voltage? Power cannot be calculated without voltage and current being known. For the PCs, maybe just say which CPU you are using at the very least, else I'll size according to PSU ratings, if that is not possible.

Also it should be fine running the printer from the UPS. The inkjet printer that is. Provide it's operating voltage at that amperage also please.

Off-The-Chart said:
my apologies if I am intruding on the op's thread, but as it is exactly what I am looking for I didn't want to create new thread.

also looking for a UPS to power the following:
i5 750
ATI 5850
2x 1.5TB, 1x 1TB, 1x 60G SSD
1x Optical
Corsair HX750W
24" Samsung

was eye'ing THIS
Click to expand...

That UPS's specs are as follows:
Maximum Power: 540 Watts
Maximum Reactive power: 900VA

Therefore the UPS is too small to provide all the power the Corsair PSU can pull, BUT, your PC won't be using nearly that much power considering the specs. Unfortunately it is impossible to say exactly how much power your computer uses I'll use ballpark based on reviews for similar hardware. I am also going for very conservative calculations so that it is almost certain the UPS would be large enough.

So from what I can see online the PC itself shouldn't be using more than ~450watt under heavy load. The Corsair HX750W, according to reputable reviews has a power factor of 0.99 at that power draw (in fact in the review power factor never goes below 0.98).
Therefore reactive power is essentially 450VA.

You don't really say which Samsung but let us assume it doesn't use more than 60watt because I have a 27" Samsung which is rated @ 14v, 3.5A. Taking a efficiency of 80% into account that would be ~60watt drawn from the wall. Because it uses a modern SMPS we can assume power factor is around 0.8 worst case, therefore the total VA would be 72VA reactive.
Therefore, PC total draw: 450W
Screen Total draw: 60watt
PC Reactive Power: 450VA
Screen Reactive Power: 72VA

Total Power: 510W
Total Reactive Power: 522VA

eg. With your current PC the APC should be able to handle the load ;)

Note however, that Corsair unit really CAN source 750w of power, therefore, at full power with the efficiency noted from reviews of 85% the PSU would be sourcing 862.5w, best to add some headway, so make it 900W.

That UPS can only supply 520W so it would overload (but the UPS does provide overload protection and will power down when that happens).
 
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spiderz said:
If you still want to work with the power off, look at laptops.
or go very big ups (5Kva+) & generator
Click to expand...

APC Smart UPS offer the ability to connect extended run batteries. Which should significantly improve the up time. Neither the APC Smart UPS nor the extended run batteries are cheap tho. Low output UPS + Generator to power said UPS will probably cost just as much.
 
man now that is what I call decent help...

thanx a lot Gnome...

glad some1 was able to handle the helping and not just point to a calculator or google (no offense to those that did),

but I wouldn't have come to ask if I actually knew WTF was what when it comes to this...

so then from your descriptions: THIS would be a more viable option?

also, what brand would be the choice if you weren't able to fork out for the APC's ?
 
As I said, the UPS you chose before will suffice unless you want to upgrade to like dual GFX cards or something in that order. The second UPS (1500VA) will be enough for an upgrade to some dual GFX configurations but not all. Honestly you have seriously power PSU so unless you plan on using every last watt that PSU can provide, you don't need such a powerful UPS (or PSU for that matter).

APC is a great brand but the Back-UPS is really their bottom of the range and not very well priced IMHO.

You can try PowerCom (Black Knight Pro), the specifications on their UPSs are for the sake of the argument, identical to that of APC. At the low end of price range that is.

Last thing, when you do buy a UPS remember that you can always keep it indefinitely. We use a 1500VA APC unit at my Moms work, bought in 2000. I've replaced the batteries twice now (battaries are around R90ea x2 from a local electronics store). So if you buy a slightly more powerful unit, you pay a large amount once and keep it for a very long time.
 
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It also pays off to get efficient power supplies if you're going to run a PC from the UPS.

I just ordered an APC Smart-UPS SUA1000i (1kVA / 750W) for my i7 940 + 2x GTX 460, seeing that my cheap Proline 600VA UPS didn't cut it.
I'm never ever going to buy a Proline UPS again, since they're building the UPS from components that are way below spec. Like my dad's 2kVA Proline UPS uses wiring that can only take up to like 600VA.

I've heard pretty good things about the PowerCom Black Knight Pro UPS' from other forumites so far.
 
Pada said:
I'm never ever going to buy a Proline UPS again, since they're building the UPS from components that are way below spec.
Click to expand...
Yeah. Got a el cheapo UPS atm...no fun. Couldn't even get it to talk to the PC. Constant 50hz buzz. Short bat life. ugh. Next one is an APC.
 
Drunkard #1 said:
jacqvt, we run everything off a SURT5000XLI (5000 kVA, 3500 W) and it's too big. "Everything" includes 6 office PCs, 4 laser printers (not all running at once), 2 dot-matrix printers, network switch, modem, router etc, ISDN CPE, POTS switchboard, laser fax, copier, alarm, lights, etc.

We don't care what it cost, because it'll always be lower than paying staff for sitting around, talking ****. Maybe go for the SURT3000XLI (3000 kVA, 2100 W). I find that calculations tend to overestimate the load, that's why I just follow my gut.



There are power consumption calculators online (not the APC one, that sizes your UPS once you already know what you power consumption is); there was a link to one in a thread once, but I can't find it. Just google it.
Click to expand...
I dont have much time on my hands these days, busy expanding our shop, and doing most of the work myself, thats why the late response. I really think we must get such a descent ups as you stated here. May I ask how much you paid for it? Or can a dealer maybe quote me? Thanks.
 
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