To UPS or not to UPS

My curiousity at work again.

I have unpredictable AC during three seasons when we have wicked electrical storms. I've lost 3 machines and some peripherals over the years before I got myself a UPS.

I personally have no use for surge protectors. While they protect you from spikes you still get rebooted when the power flickers. Surge protectors do nothing for voltage sags either. Having said that, my laser printer is on a surge protector as it draws too much power for all but the biggest UPSes.

So, every item of computer gear I own is plugged into a UPS. This includes my adsl modem, my router, my hpc chargers, my digital camera and my bedroom TV (which is a 17" Compaq monitor)

In all I have 5 UPSes scattered about the house. I'll add I haven't lost any gear or data from power problems in the last 7 years.

You caught me by surprise. When I saw the thread title, I thought, That's gotta be wally sharing more United Parcel Service horror stories.

I don't have any UPSs, believe it or not. That's one nice thing about H/PCs - theoretically, you can avoid exposure to power outages/surges entirely. (I have a rechargeable external power supply with a range of 4-9 volts, and a power inverter in my car, so I can charge my H/PCs without even looking at a wall outlet.)

I think a few folks will get fooled by the title until they read the post.

I lost a laptop that was plugged into AC to charge. The surge smoked the adapter and continued on into the laptop guts and fritzed the mainboard. Shortly after that I got my first UPS.

You don't need a UPS to protect against something like this. A simple surge protector will generally do the trick. Indeed, a power surge big enough to fry a laptop through a DC brick is probably going to trash a UPS.

I have two heavy duty UPS devices next to my desktop to insulate against surges, brownouts and all sorts of lovely transients. Anythings I would care about loosing are plugged into battery backed ports, with everything else plugged into the transient protected outlets on the UPS. I also use much larger power supplies than strictly necessary for all my computer, which adds an extra level of protection. Oh, and for those who don't know amps from volts, try to keep high draw devices like a laser printer, space heater, mini-fridge, stereo system, etc. disconnected from the UPS. You should also check to make sure that your outlets are truly grounded by removing the faceplate and making sure there is a third wire. I have found many older building will have 3 prong outlets, but the third prong will be disconnected or be connected to a very inadequate ground.

hehe. that's one reason why i like external battery chargers & spare batteries.



what is included in the "etc"?

to answer the question, i have exactly one UPS here. have had it for a few months only, but it already has served me well on several occasions

it is really really fun when you can still do wlan with the hpc for long long hours when the power is out. (router and adsl modem is powered off the UPS of course )

but i don't charge my hpc's (the ones that have no external chargers) off the UPS. i plugged in my sig3 (the first one) after buying the UPS and the sig3 didn't like it, so i decided i won't try it again. maybe just this sig3 is so picky though. i may reconsider the idea of charging the hpc's there.. i dunno. what's your opinion about this?
(currently i plug them in surge protected theoretically, by some APC surge protector)

anyway, PC, tft monitor, router, modem use the UPS (600VA, hope that's OK), and that's about it.

Edited by cmonex 2006-05-06 7:36 AM

Interesting. There are some things that don't like being run off inverter power because of the waveform of the AC. (Flourescent lights hate square waves for some reason. ) Does the SigIII run directly off wall power or does it have an AC to DC adapter? i.e. Is it a simple cable to plug in to the wall, or does it have a 'brick' in the middle of the cable or a 'wall wart' at the end that plugs in to the wall? I've never seen a brick or wart that couldn't handle the power from an inverter.

sig3 like any other hpc accepts dc only so yes it has an ac-dc adapter.
but i run the whole thing through a voltage converter, 230V-110V, the sig3 adapter is 100V and we have 230V here... hmm but 110 should be ok, shouldnt it?
so if you have any ideas let me know..

Ahh, yes of course. That does coplicate things.

Is your UPS a 115V or a 230V UPS? If the output on the UPS is 230V, and you use a stepdown transformer on the output, that might cause problems. [I don't really know enough about AC voltage transformers to know how they react to square wave versus sine wave voltage. Normal wall voltage has a sine wave phase, while UPS and inverter voltage is typically a square wave phase.]

Which brings up another question: Do you happen to know the phase frequency of your AC? North American AC is typically 115V (plus or minus - my wall voltage is usually 122V) at 60Hz. If the phase frequency is much lower than 60Hz, that could really screw up a DC power supply.

[Side note: Different countries do use different phase frequecies. For example, UK uses (or used to use) 50Hz AC instead of 60Hz. This is why PAL television uses 25 FPS video, while NTSC uses 30 FPS. Back in Ye Olde Days, televisions used the AC phase frequency as a sync clock for displaying the video. Frame rate had to be equal to or an even fraction of sync clock. Brits had 50Hz AC, Americans had 60, so we had diferent video standards.]

Your best bet would probably be to have a 115V UPS (which should accept input voltage of anywhere from 100V to 130V just fine) and use a voltage transformer to power the UPS. You'll probably need a hefty transformer if you run a lot of thing off it, as the converter will need to handle the current of any device attached to the UPS, plus the UPS charging circuit.

well, i should clarify some things (?)

the sig3 is japanese and its ac adapter accepts 100V input, NOT 115, this is not a US ac adapter. since japan has 100V. i use a voltage converter aka stepdown transformer (do i understand right? ) to charge the sig3: 230V outlet -> 230V to converter -> 110V output to sig3 ac adapter -> 9V dc to sig3

the UPS is 230V as that's the standard here.
and i believe we have 50 Hz rather than 60. (but i have no idea what this means! )

so this is the problem?

the voltage converter i use just outputs 110V, doesnt tell the phase frequency but i guess it should be 60, and the max power it can output is 100W.

what do you think about the difference between the japanese 100V and the us 115V? could it matter?

i'm not sure how much such a transformer would cost, it would have to power the PC, the monitor, the UPS, etc... or if i can find such a transformer at all

Well, a 100V adapter should be OK with 110V. Most equipment in the US is rated at 110-115V, even though typical municipal utility AC voltage is in the 120-125V range. (My UPS monitoring software is reporting a wall voltage of 122V right now.) Putting 125V on a 100V device could be a problem, but 10 volts overage should be within tolerances for the AC to DC converter. So I doubt that's your problem.

So, just to be clear: You plug your 230V to 110V stepdown transformer in to your UPS, the plug your SigIII AC to DC converter into the stepdown transformer. Does this cause a problem for the SigIII when you plug the stepdown transformer directly in to the wall as well, or only when you use the UPS? If it's only a problem with the UPS, but not when plugging the stepdown transformer right into the wall, then it's probably a phase waveform problem. I would be suprised if this was the problem, but it sounds like this is the case for you. If the SigIII doesn't like your stepdown transformer either on UPS or wall power, then it's probably a phase frequency issue. It could also be a combination of the two: i.e. the SigIII AC to DC produces reasonably acceptable DC voltage with either square waveform phase or under frequency phase AC voltage, but when you give it both a square wave and a frequency that is too low, the DC voltage is just too unstable and the SigIII doesn't like it. It's unlikely that your voltage converter can step up the phase frequency from 50Hz to 60Hz - that's a lot more complex device than something to merely step the voltage down.

Don't worry if you don't understand what a phase waveform or phase frequency is. All you need to know is that your UPS, when running on battery power, is probably putting out a 50Hz square wave, while your SigIII power adapter probably wants a 60Hz sine wave. A US/Japan UPS would put out a 60Hz square wave when on battery power, which the SigIII might like better. The voltage converter you use to step 230V down to 110V is probably just that - a stepdown transformer that doesn't alter either the waveform or frequency of the AC phase. Even if the AC voltage is correct, these other properties of AC power affect how the AC to DC converter works and what voltage you actually get out of the DC end of the converter. It could be the combination of the two is just too much for the SigIII to cope with.

yes you do understand correctly the setup of the various ac adapters and ups's and transformers

your explanation is very clear and what you say really makes sense.

my sig3 is picky otherwise too, in one certain outlet it starts charging OK, in another it doesn't (but it will start up after a little while, thats better than nothing) and this is consistent. also it doesn't depend on battery charge level or anything. but your explanation makes sense except for this phenomena, why is it OK in one certain place and why not in another... too bad the UPS didnt help with that.

(hmm didnt try charging the other sig3 yet. lets see.. )

Edited by cmonex 2006-05-06 7:30 PM

Not only do I use a UPS on all of my computer gear, but I have one for my TV as well. My TV is a 36" JVC hi-def tube. It gobbles electricity like crazy, so my UPS lasts only about 40 minutes with it and the DirectTV receiver plugged into it. But that is long enough for most of our temporary brown-outs.

And like someone else said, surge protectors are good for lightning strikes, but useless for voltage drops which seem to plague me more often than anything else.

Rich

wow, and for how long does your PC run off the UPS? i'm probably lucky to get 15 mins off mine. (never tested it fully, as i wanted to use the remaining battery power for the router and modem LOL)

AFAIK most TVs will use less current than an average pc. IIRC my 25" TV uses 1A or about 115 watts. I'll try and find the manual to verify it.

I have my UPSes set to shut down my gear 5 minutes into a blackout. They could run longer but since I'm not a 24/7 DP center there's no point.