OT: killed my computer



"active" - better known in the computer and power conditioning world as "dual conversion"
"Line interactive" is one step down but adequate.
Standby is bottom of the line - it has a "switching time"
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Anything that the $500 UPS might accomplish is supposed to be done even better by the computer's power supply. After all, what does that $500 UPS do? Its power supply simply does same as a computer power supply does, then creates what is often electricity dirtier than found on AC mains. Well, yes, the $500 UPS is cleaner than the computer grade (sub $100) UPS. But that makes no difference to a computer. Some of the dirtiest power comes from a computer grade UPS when in battery backup mode. Dirty electricity that must be completely irrelevant to any computer because of what all computer power supplies did even 30 years ago.
That UPS accomplishes nothing for the OP's problems. And if 'dirty' electricity was causing power supply failure, well, the market is chock full of power supplies missing essential functions. Why? Because many if not most computer assemblers don't even know how electricity works. That creates a market for power supplies (missing essential functions) that sell for less money AND have higher profit margins.
Power supplies marketed to the electrically naive would then fail more often. So what do the naive then do? Buy a $500 UPS instead of spending $25 more for the power supply? That bean counter's mistake is why some recommend unnecessary $500 UPSes.
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On Tue, 2 Dec 2008 13:11:30 -0800 (PST), snipped-for-privacy@gmail.com wrote:

Sorry, but as a professional I have to dissagree with you. ONE of the major problems affecting computers is HARMONICS. ONLY a dual conversion can protect bothe the computer and other devices downstream from Harmonics. Switcher power supplies can cause harmonics. Power lines can amplify them.
A separately generated power supply in a good dual conversion UPS is CLEANER than the vast majority of the North American powwer grid.
Power ripple is a major contribution to power supply failure - that is otherwise known as "noise"

And I have had to replace some VERY EXPENSIVE designer PC power supplies. Like $400 power supplies (crazy, eh?)
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snipped-for-privacy@snyder.on.ca wrote:

Sorry, but as a professional I have to disagree with you. :)
Harmonics is NOT the big problem it is often made out to be.
A DC ups will only protect you from voltage harmonics, and even then, if the major source of harmonic currents are on the downstream side, they can only do so much.
And if we are talking about a standard (Cheap ass) non power factor corrected PC power supply, it can actually be happier with a voltage input that looks more like a square wave. [Lots of 3rd & 5th]

Power lines do NOT amplify harmonics. They are subject to ohms law just like any other electrical circuits. THe power lines have different impedance at different frequencies, but most harmonic sources act more like constant current sources, than constant voltage sources.

Not generally. Failures are due usually to increases in voltage either long term or momentary (surges). Noise is generally considered as a high frequency (relative to the power line) phenomena, and isn't generally considered as a cause of failures.
jk
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What is the major hardware failure in today's PC's? Bad electrolytic caps on the motherboard or in the power supply. They are crappy caps with a defective water based electrolyte - to be sure - but it is stated that high ripple currents are responsible for appreciably accellerated failure.
In one office I service we had 8 computers bought at the same time, with identical motherboards and power supplies. The 3 that were on UPS protection from day one are still running I think about 5 years later. I believe one power supply has been replaced. Three that never had a UPS are long gone with swelled motherboard caps.(after at least one power supply each) The other two went onto UPSs after about 2 years, and both have failed over the last several weeks with swelled caps and are on their second or thiurd power supplies. Several hard drives have also failed, but not on the 3 that have spent their whole lives protected.
As for power lines not amplifying harmonics, what exactly is resonance, and how does it affect amplitude??? Resonance downstream from a harmonics generator CAN amplify the resonance, and even feed it back to the source.
The other problem dual conversions are good at solving is common mode noise. And how about floating neutrals? Not out of the ordinary in many commercial apps to have the neutral several (or even tens of) volts above ground.. Ither an isolation transformer or a dual mode UPS can solve this problem. ONEAC made a fortune selling isolation transformers untill the cost of a Exide (now Powerware/ Best?whoever)Prestige UPS got low enough to undersell an Oneac and a cheap miniteman standby UPS.
Played havoc with thesale of the old Sola line stabilizers too - and at least an order of magnitude more efficient.
Every mission critical computer I spec or sell goes with a MINIMUM of a line interactive UPS - andif at all possible a dual conversion (true online) unit.
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On Dec 3, 11:32pm, snipped-for-privacy@snyder.on.ca wrote:

If harmonics are causing failures, then harmonics are also destoying a UPS power supply - for same reasons. Correctly noted is that harmonics are not a problem to any properly constructed power supply. However, harmonics cause problems elsewhere such as in building wiring and utility power transformer. Harmonics are why a shared neutral wire must be larger than required by code.
Best harmonics solution is a computer with PFC. That eliminates a problem at the source, makes the computer even more resistant to external harmonics, and reduces energy consumption.
A professional? One who learned this stuff by designing things or one who only knows by observing some machines? This poster agrees with jk due to a few generations of actually doing this stuff at the electrical level. Who learned this stuff by actually discovering why electrolytics failed and even which manufacturers were more prone to particular problems? jk is correct. If harmonics were a problem to any computer, then the purchaser must identify himself as a reason for those defective computers.
Harmonics made even less problematic by PFC circuits in that computer's power supply - which are commonly found in Europe where international standards apply, but not required in America.
A computer must be so robust as to make high harmonics from any typical computer grade UPS completely irrelevant.
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snipped-for-privacy@snyder.on.ca wrote:

Cap failure on the mother boards would be a clear indication of crappy power supplies.

WHich would be regulation and filtering in the power supply, and nothing to do with harmonics

It is exactly the same thing it is in ANY R-L-C circuit. Under "ideal conditions" it presents either a 0 impedance or infinite impedance [depending on which sort of resonance].
If you have a source that acts as a constant current harmonic generator, then an infinite impedance at that frequency forces the voltage to increase until the current source saturates.
This is no more "amplification" than a transformer is an "amplifier". The total harmonic energy does not increase in resonance, it just gets converted from a higher voltage- lower current manifestation to a lower voltage-higher current one (or vice versa). THe power line does not "magically " convert it's power into harmonics vis some mysterious "hoodoo" at resonance.
YOu can have a resonant circuit just sitting there all the time without a problem, until you start exciting it with some energy at its resonant frequency. That energy however does not come from the power line directly.
Instead, it is a non linear load (such as your PC power supply) That takes energy at the power line frequency, converts most of it so some purpose, and converts some of it to a different frequency, and pumps it back into the system.

WHich is also a from of a common mode problem.

"tens" would be highly unusual. 3-5 v is pretty common.

They only solve it if they are electrically close to the load.

Yes, but the SOla's are not near so maintenance intensive. [Assuming one does maintenance. So many places don't]
jk
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jk wrote:

Bullshit. The caps that fail are part of the on bioard swithing supplyt for the CPU and they fail because they are cheap crap.

The harmonics cause problems in older builings using three phase power, and undersized neutrals. This problem was known 25years ago, yet contractors continued to do substandard work. Some offices had electrical fires after a lot of PCs replaced old dumb terminals that had linear supplies, with full wave rectification. The 120,000 sq ft Microdyne facility that used to be near here had constant problems with equipment failures, until they finally pulled a second neutral to parallel the original neutrals. Computer & test equipment failures dropped by over 90%.

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Or something in-between. When have you ever seen a tuned loop that was perfectly resonant? (the matter is called "Q")
LLoyd
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"Lloyd E. Sponenburgh" wrote:

I didn't write that, but I am quite familiar with 'Q' (Quality). I was a radio & TV broadcast engineer, I've built custom telemetry receivers for NASA, NOAA, the ESA the ISS and the aerospace industry. Electrolytic capacitors have a limited life span, generally 2000 hours at the rated temperatures.
I built a seven stage filter to remove a single channel from the CATV feed at a school. The 'Q' was high enough that the 1 mV RF input would give a nasty shock. It was built in a Bud diecast aluminum box with an internal shield made of sheet brass to divide it into separate compartments. I built it with torroids & glass piston capacitors for the series tuned stages, and tuned core inductors with polystyrene capacitors for the parallel tuned stages. It was used to replace a scrambled CATV channel with the school's local ETV feed.
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On Tue, 2 Dec 2008 13:16:03 -0500, the infamous "Buerste"

You 'splain me, Tawmy? (No info was found online during a quick googling for it.)
I've always had passives and they've worked fine. Who makes actives and what's the price differential?
-- The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man. -- George Bernard Shaw
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WHat he defines as an "active" UPS is more commonly referred to as a "double conversion" ups.
In a double conversion UPS all of the power is converted to DC, to feed the DC bus and charge the batteries. THe DC is then turned into (via an inverter) AC that is completely separate from your AC line. When your input goes away, you just continue , but start discharging your battery.
THe other type of ups, feeds input power straight out to the load, and also charges a battery. WHen it senses a power problem, it starts the inverter and then uses a relay to swap the output to it. Not a big deal if the problem is a slow rise or fall in the voltage. But a surge, or a total outage,[or other high speed events] which travel at effectively the speed of light, reach your power supply before the relay can do any thing about them.
OTOH, they are MUCH cheaper.
[I have also had the fun of listening to them oscillate in a server room. As they decided the power was OK again, they all [1 SUPS per server] switched back at the same time [Factory default]. THis caused enough of a sag [when the line voltage was a little low, while doing a generator test] that they all switched back to battery, but then the power was ok again, so they all switch back to the line.....and so on and so on.]
jk
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jk wrote:

An "Uh oh!!" moment. You go to High Alert, your gut says that you have to do something, FAST!, but you don't know what to do! But don't do more harm than good! What to do, what to do ...??
Bob
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jk wrote:

That last bit is why once a site is big enough to have a "server room" of any consequence, the little individual UPSes need to go the way of the dodo and be replaced by larger "real" UPSes. When you get big enough you have multiple huge UPSes, battery rooms, static transfer switches, etc. and "real" power management.
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wrote:

And somewhere in between a few good midsize dual conversions give you the capacity for some redundancy. You ARE running redundant servers, are you not???? What good are redundant servers if they are taken down by the failure of une UPS??
We have 2 servers, one with redundant power supplies, one without - with one UPS powering each power supply on the dual supply unit, while the single power supply unit takes one UPS while the"maintenance" workstation takes the other.
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snipped-for-privacy@snyder.on.ca wrote:

We have UPSes with battery rooms feeding three phase 480V static transfer switches and PDUs, backed by big diesel generators with lots of fuel. Nearly every piece of equipment has N+1 power supplies fed from separate PDUs on separate UPSes. Redundant servers are in different states.
At home I'm a little more lax with single UPSes in my office and on my server rack in the garage, backed by two generators, one as primary which I typically have online in 5 minutes and one as backup which can be online a few minutes later if need be. Server rack UPS gets around 45min or better of battery run time.
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    [ ... ]

    Well ... I have one serious server (a Sun Fire 280R) with dual power supplies in the server, and in each of the two trays of Fibre Channel drives. One side of each is plugged into the main UPS, and the other side is plugged into the incoming AC line through a surge suppressor only. This way, I am protected if the UPS dies, or if the incoming power does, but not if both. The other two (smaller) BEST UPS are only 1400 VA and 700VA and each support a single machine.
    The main UPS also runs two Sun Ultra-10 machines acting as web servers, two Sun SPARCstation 5s acting as mail servers, an Ultra 5 configured as a firewall, the Cisco router/CSU/DSU for the T1 line, and on occasion a Mac Mini.
    As for the earlier mention of the Sola style transformers in the FERRUPS' being rather inefficient unless the system is fairly loaded -- each UPS is running about 75% of maximum, so yes, it is loaded.
    Oh yes -- on the server, the tape jukebox only has one power line, so that goes to the AC line only at present. If the power is gone, making a new backup is not going to complete before the batteries in the UPS get to the point where it tells the systems to shut down. :-)
    But, of course, this is a private system, with no income so I can afford to take some time to rebuild things if necessary.
    Enjoy,         DoN.
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    Well ... there is a third type, exemplified by the Best Power Systems FERRUPS which I have on several computers.
    These bring the power in through a ferroresonant constant voltage transformer (like the Sola ones) with some extra windings. The line power is also used (separately) to maintain the charge in the battery or batteries (one of mine -- a 2KVA one -- uses four *heavy* 12V gel batteries in series). The ferroresonant transformer does an excellent job of protecting the load from surges and such, as well as keeping the systems happy during brownouts.
    When the power goes away, those extra windings are driven by the inverter to maintain the voltage. There are no relays involved, and switchover is fast enough so the load doesn't have a chance to notice it.
    These every so many hours will switch on the inverter to verify the state of the batteries, and then switch it back off. Ever so many days it will do a "conditioning" charge cycle on the batteries.
    Best Power Systems is long gone -- but their products still show up on eBay -- sometimes for very good prices -- so I have three of them, one powering a two racks full of computers, and the other two powering two Sun Blade 2000 computers, with the larger one also powering a seven-drive tray of Fibre Channel drives running as a RAID assembly. (The racked computers also have two such trays running.)
    Enjoy,         DoN.
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wrote:

And the ULTIMATE UPS us the Best UBS system. Available in diesel, gasoline, propane and natural gas they are a DC generator unit to match the battery voltage of the UPS that is automatically started X minutes after a power failure.
UBS for "Unlimited Battery System" Fantastic units and were common in emergency services departments in storm-prone areas - Hurricane in the south-east, Blizzard in the NorthWest, and Ice Storms in the North East.
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"DoN. Nichols" wrote:

Just realize that you need to keep those FerrUPS units operating at near their rated load or you're spending a lot of money on wasted energy.
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