Author Topic: UPS sensitivity by brand and adjustment questions  (Read 6317 times)

cujet

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UPS sensitivity by brand and adjustment questions
« on: February 28, 2007, 12:05:03 PM »
In another thread, I spoke about the ST power not powering my house properly. In particular my APC NS 1050 and APC back pro 1100 will not tolerate ST/Lister power.

It seems the 1050 has a voltage sensitivity adjustment. The 1100 is supposed to auto condition power, even during a brownout. Neither seems very good at it's job.

So, has anyone here had success adjusting APC UPS's when using ST power?

Is there a different brand I should consider? How about some form of line power conditioner (transformer?) placed before these UPS's?

Suggestions please!

 
Note: I run at exactly 60HZ under load, I have extra heavy flywheels on my 20/2, I have the 70 pound extra heavy gen head pulley, the governor linkage is fully heim, the gov spring is able to control freq within 1-2 from no load to full load. My loads are generally steady.

Chris
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rmchambers

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Re: UPS sensitivity by brand and adjustment questions
« Reply #1 on: February 28, 2007, 12:59:18 PM »
The APC ups's are ok for a fairly cheap UPS.  Their tolerance for less than great power though is not very large.  There is a small button on the back of most of them to adjust the sensitivity (the green LED is bright, medium or dim corresponding to sensitivity) but other than that there's not much you can do.

It may be the superimposed peaks on the sinewaves that throw the UPS off.  I've had experience with APC, Best Power, and Liebert systems.  The APC are the pickiest of the lot whereas the Best power and Liebert (larger systems though) seem to ride out a little better.

Not that you're looking to spend even more money but the output from a Trace/Xantrex DR series inverter is perfectly acceptable to an APC UPS.

If you're running your house on ST generated power and having some battery backup is in your future then you can use the UPS after the Trace Inverter (sort of a UPS to the UPS) and you should be ok.

If you're not planning a battery storage system then you need to figure out a way to clean up the waveform from the ST.  The AVR project may be of help once that gets done.

Robert

mjn

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Re: UPS sensitivity by brand and adjustment questions
« Reply #2 on: February 28, 2007, 04:50:42 PM »
I have two UPS systems.  One is a cheap 400va Belkin.  The other is an APC SmartUPS 450va.

The Belkin is perfectly happy with the power from my ST head.  The APC does not like the ST power, and stays on battery until the battery goes flat.

The APC model is an older one, so it does not have the sensitivity adjustment button.  I have been unsucessful in getting a software driver to talk to the UPS to attempt to make it less picky about the frequency and voltage. 

I'm looking for somebody who wants to "upgrade" their Belkin with a nice "SmartUPS".
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Tom

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Re: UPS sensitivity by brand and adjustment questions
« Reply #3 on: February 28, 2007, 06:16:58 PM »
I have an older Tripplite UPS/power conditioner that has survived a lightening strike over a hundred hours on various generator power (no st though) and has performed like a champ. The lightening strike burned out ALL my surge suppressors and half the appliances that were plugged in at the time.

This unit has conditioning from 90 to 140 vac and there was a period of time when it showed high voltage. So I contacted the utility co and when the guy showed up and took a measurement he said hum, 1 volt over spec, how did you know that. The only problem with this ups is that it is now ready for it's 3rd set of batteries.
Tom
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ronmar

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Re: UPS sensitivity by brand and adjustment questions
« Reply #4 on: March 01, 2007, 06:13:46 PM »
Chris
   Even if you open up the tolerance a bit, I don't think you will get them to work.  The fault most likley lies in the way they sample the frequency.  Your UPS's now most likley have a +/- 5% tolerance in frequency.  At 60HZ, that is +/- 3HZ and even a sloppy governor on a listeroid should be able to maintain this 57HZ-63HZ window most of the time.  If you can get access to an O-scope and look at the output power, you will see that your harmonically excited ST output most likley has multiple peaks(this is what messes with microwaves as they probably see it more as a flat topped peak) and occasional humps on the upslope and downslope most likley caused by the diodes chattering/ringing as they close/reverse bias.  These additional peaks are seen by the UPS so it is probably seeing a very high freq, one way outside any tollerance adjustment capability you may have on the UPS.  If you feed the field winding with pure DC(not derived from the "Z" winding), you get a pretty good looking sinewave. 
PS 6/1 - ST-5.

Geno

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Re: UPS sensitivity by brand and adjustment questions
« Reply #5 on: March 01, 2007, 07:06:40 PM »
I have a PowerSolutions ST5. Before I ran it I put new bearings in, cleaned it well with the right cleaner, made sure all the connections were good and sealed everything with electrical urethane. I have a Radio Shack rectifier in it. I don’t know if these things helped clean up my power but I can run a fairly advanced Oneac 1.3KVA ups and a smaller 900VA as well. The 900 might bitch a little but will come on line. One of my clients bought a computer grade generator for his computer system and it wouldn’t run an identical 1.3 until we got a 40% load on the genny. I’ve never put a scope on it so I don’t know what the power looks like. Both UPSs have simple serial interfaces and I need to hook into them to see what’s what. My engine keeps a pretty steady rpm with a cleaned up, stock linkage.

Thanks, Geno

Dustpile

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Re: UPS sensitivity by brand and adjustment questions
« Reply #6 on: June 26, 2007, 08:19:32 PM »
Have a look here  http://emergencypower.com/power-problems.htm 

What you may be finding is line noise that the UPS trips on. Make sure your generator is well grounded and eliminate noise such as variable speed motors and light dimmers.


evilpsych

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Re: UPS sensitivity by brand and adjustment questions
« Reply #7 on: October 07, 2007, 03:22:57 PM »
might i suggest another option for you UPS users that also have a battery bank?

run a 24vDC lead to your UPS battery connection from yoru main bank. Start the UPS normally but with no load (such as off an inverter or on st power), then unplug the AC cord.. now it's running right off the batteries.. all better UPS's are basically a double inverter ac->dc->ac with their own 60hz generator.. by hooking it into your constantly charged battery bank - you fool the UPS into thinking that it has a larger capacity than it actually has. I replaced my UPS batteries with a pair of 31d Deep-Cycles which are in my basement.. translates to about 12hrs of runtime if the power's out..

If you setup a few of these, power-line conditioning becomes fairly easy without worrying about funky ST noise. just a thought... last i checked, you can get probably 50 UPS's on ebay for the cost of a house house inverter.. .

ronmar

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Re: UPS sensitivity by brand and adjustment questions
« Reply #8 on: October 07, 2007, 05:58:14 PM »
That is a good idea in theory, but the UPS's were rated for backup power, not a 100% duty cycle.  Since they were designed for emergency backup usage, they are just not built that robust. Their biggest shortcomming is that they are made small so cooling for the SCR's will be marginal(usually have no blower/forced air over the heatsinks).  They are also not especially efficient.  I know they monitor their own input battery level, but I am not sure they monitor their inverter output power, so how exactly they would fail is anybody's guess.

I posted the particulars in the "ST POWER USELESS" thread a while back, but I was able to get my ST to power a triplight reliably with a little filtration(capacitance) on the rectifyer output.  This cleaner DC to the field winding increased the generator output voltage so some high wattage resistance on the field supply was needed to get the output voltage back in spec.  This cleaned up the waveform a bit and removed/reduced the multiple waveformes that were most likley causing the UPS to not accept the power.     

Ron
PS 6/1 - ST-5.

evilpsych

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Re: UPS sensitivity by brand and adjustment questions
« Reply #9 on: October 08, 2007, 12:28:26 AM »
That is a good idea in theory, but the UPS's were rated for backup power, not a 100% duty cycle.

yeah. That is an issue, however, you're never supposed to run them at 100% anyway.. more like under 75%. running one at 20% capacity or even 50% capacity for short periods of time, such as for tv, using your computer, etc. If you're on a budget, and have extra battery capacity or are having problesm with your genset causing problems for your equipment, it's worth the added inefficiency, at least to me anyway

there's a load of computer related DIY UPS stuff on the net, using everything from automotive battery chargers and DC->ac automotive inverters.. to hacking off-the shelf UPS units.. it's worth a look for those of you with minor problems..
http://www.dansdata.com/diyups.htm