Line conditioner protects against momentary brownouts?

If you are worried about the transition, get a system that runs on inverter 100% of the time... These systems produce no transiet conditions or changeovers--they simply stop charging the battery when line voltage is bad. Keep in mind they are more expensive, big and heavy!

(nice thing is that they can correct for a couple of things such as bad frequency regulation (usually from backup generators) but keep running since the charger can handle wrong frequencies. They simply continue to output a rock-sold 60 hz voltage.

One company has the best of both, but still big heavy and expensive.

A ferroresonant transformer that will keep the power up long enough for the inverter to make a seamless switch, and long enough to stop instantaneous dropouts and noise from ever appearing on the output.

I forget who makes them, but we had a few at work and they were very effective at stopping all manner of line noise and problems.

"Brick Wall" Pi filters are pretty good protection from switching transients. Nothing works better than filtering noise at the source though... I put a home brew common mode CLC filter on the 220V into my electric range - only thing that would keep it from talking to my computer and phone lines.

I disagree. An UPS which ac-dc dc-ac conversion is more prone to failures than an UPS which just sits still and only delivers power when it is really necessary. The PSU in equipment should be able to deal with skipping a few mains cycles anyway so there is plenty of time to switch to battery power.

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------

The true sine inverter is the way to go. For one thing, you can really kill spikes if you do the rough conversion to DC then filter/suppress the hell out of the DC. Filtering spikes on AC isn't as easy. The disadvantage to the inverter scheme is noise. The inverter runs all the time, and even with high efficiency needs some cooling, hence fan noise. I suppose another disadvantage of the true sine inverter is that it costs money. The "modified sine" (really a square wave) is dirt cheap. In theory, your computer gear should be able to handle such a crappy source. In practice, I ruined a notebook power supply with a modified sine and made it a point to never use one again unless it was followed by an isolation transformer to take out some of the ugly edges. This is OK for low power stuff.

I have a few of the relay/transformer type regulators. OK I guess, but often wondered how big of a spike they make. Fortunately, mine rarely switch.

In the military, they use online motor-generator thing. This provides switching to the backup power without any interruption of a cycle. This also acts as an ideal filter blocking the leakage of the information into the power lines, and it decouples the internal power from external, protecting it from any kind of glitches or EMP.

VLV

There was a company which made a very cheap fail safe solution for computers. That was just a bank of capacitors with the charging circuit. The computer was powered from DC. When the input AC failed, there was enough of energy to save the current state of the computer onto the hard disk. They had an MS DOS driver to save/restore the current state automatically. There wasn't any problems except with the degaussing circuit of CRT monitors :-)

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Then explain the pallet loads of dead UPS that show up at government auctions from military bases.

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Politicians should only get paid if the budget is balanced, and there is
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FWIW.

I was talking about a 1200 watt line conditioner (that includes a voltage regulator), not an Uninterruptible Power Supply (UPS). There is no battery.

I have no use for a UPS. And I believe most UPS users are wasting their money. If you have blackouts frequently enough to lose important data, you have too many blackouts. But seriously, the average user risk of Windows crashing, freezing or spontaneously rebooting, is probably much greater than a blackout. And when Windows crashes, a UPS does not help. Windows has taught me to never leave data unsaved for more than a few minutes.

Of course I am not talking about a company with critical data and/or data that must be continuously accessed, or something else like that.

Spontaneous rebooting of Windows went from annoying to zero here after starting to use a cheap voltage regulator, for years. Too bad I did not try one back in the Windows 95/98 days to see if maybe it would have helped. The horrible memory management was known to cause crashing, but maybe a voltage regulator would have helped.

Now brownouts are the only risk here, prolonged under or overvoltage is no longer a problem, so it operates only momentarily and I wonder whether that does good. I definitely like the visual indication that the house voltage is correct, but that could be done more easily.

Anyway, as always, I enjoy the discussion.

: ,

nt

Much government gear comes from contracts that expired. When the contract is over, all the gear is dumped.

Besides a good PC power supply or better wiring, what retail product best corrects momentary lags in voltage like those caused by starting an air conditioner? Is there something better than a device like these?

I wonder about the products made for home theaters, since apparently they do not include anything for momentary low voltages?

Not military scrap. It's just that. Beaten, broken and not usually worth fixing outside of a depot. Or no one bid low enough to get a contract to refurbish that lot.

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

It was possible Best, and I think they finally dropped those things.

they were very inefficient and really really likely to fail/shutdown if you tried to use them with a generator.

I agree. I used to have an UPS (actually several) for years but it turned out the UPS was causing more problems than it solved.

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------

Living out in the sticks, I tend to get blackouts lasting a couple of seconds every time there's a thunderstorm. Without a UPS, the PCs would effectively be unusable for half the night (there's no point using it if it's going to reboot at any moment).

FWIW, I find WinXP to be quite stable, with most reboots being down to driver upgrades. But I do tend to avoid running anything which isn't necessary; it's likely to be worse if you have kids loading the system up with junk.

For me, Win95/98/ME would crash several times a day due to memory issues. You would have to have truly awful mains to add significantly to that. OTOH, I was using it for software development, which probably affected the crash rate somewhat.

Totally inefficient - but the company I worked for walled-in whole banks of fluorescent lights and left them turned on and connected. Green was something for hippies and weirdos and global warming a hoax.

We did have a large diesel ~100 KW and didn't have problems with the power transfer glitches dropping the UPS off line.

Right... If you live in the sticks, have frequent thunderstorms that cause blackouts, and do not disconnect stuff to help avoid your hardware being fried by lightning strikes, you can use a UPS.

Or, if you are a company with critical data and/or data that must be continuously accessed, or something else like that.

There are lots of possible exceptions, but the point is that many ordinary PC users who think that they need a UPS probably do not. You can see the ignorance in product reviews. Many UPS end users are probably just infatuated by the idea of running their PC on battery power for a while.

Yep, lots of reasonable theory there, I just wish I had the proof.

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that's a fairly large generator, and probably would not slow down enough when you throw a ferroresonant transformer on it to cause the transformer to act goofy or lose its field and then try the batteries, then notice the generator is upto speed- repeat until the batteries are dead.

It's interesting that they'll tolerate any garbage waveform input, but the frequency must be nearly perfect or they just don't work.

I was like that for a while, but mostly to try to rig up some extended run time on ~650VA UPS by attaching it to a larger set of external batteries to try to get a somewhat meaningful runtime out of it all.

I forgot about one part- junior UPSes are not designed with proper cooling to run longer than their batteries will last which is usually minutes.

So I was "testing" my UPS to see how long it could run all my junk and there was a giant bang and cloud of smoke as the UPS overheated and exploded all the power transistor or SCRs or whatever it was made with. Whoops.

I think the word ferro"resonant" has something to do with that - they have transformers with a magnetic shunt(?) and a capacitor to resonate the primary? Primary probably just skates along tuned to 60 HZ - power fails or glitches and it is still ringing for a few cycles longer with the resonant circuit.

I never had a cause to tear into our UPS systems except to replace batteries but I did see some ferroresonant power transformers in the

60's in TV sets. They all had oil-filled caps across a winding (and I think the winding was only for the cap - nothing else loading it, and I seem to remember the shunt was between the primary and cap winding, but that was a long time ago).

I worked for a guy that designed the Topaz Ultra Isolator line of transformers. We did something called "box shielding" on some specials (specials = expensive special purpose). The idea was that the primary and secondary windings were both encased in a copper shields and the electrostatic shields were brought out separately for different grounds (earth and circuit?). I think the actual Topaz transformers were ferroresonant as well as box shielded - weighed a lot with cast aluminum end covers and dissipated tons of heat especially with no load.