UPS problems with electrical generators

[nova]

Looking into my suspicions:
q"There are many people in the generator and UPS industries that have tried to operate engine driven alternating current (A.C.) generator sets (gen-sets) and uninterruptible power systems (UPS) together. Although some systems are successful, there are problems that can occur."/q
http://iso9k1.home.att.net/ups/ups.html

So i'm wondering about UPS compatibility issues.

I'm looking for a few people willing to test their generators with their UPS
to see if any problems arise.

for the ones testing:
> please state your generator and UPS brand + model.
> did your UPS ever switch off from battery mode (and to the gen) once plugged into the generator?
> did your lightbulb and computer work normally on the generator powered UPS?

thank you!

[Per Hansson]

Re: UPS problems with electrical generators

I would not do this on a "normal" UPS

because the normal on-line UPS devices do still not regulate the sine wave voltage output from the outlet unless it deviates from the specefied input voltage which could be in the range of 210-260v for example...

And as you are probably aware a generator can output a totally "wierd" sine wave, and even though a SMPS is really accomodating for "rough" power you will still be able to kill it with to poor power...

There are a few models from for example APC, the Smart-UPS "RT" I think that always regulate the power... These would be ok to run on a generator... Otherwise you could of course run a computer on any crappy UPS as long as the generator supplies a voltage that is good enough for it, but it will always be the generator that supplies the computer(s) with power unless you have one of the really expensive UPSes I mentioned which always regulate the power...

I've got one in my basement but to tell the truth I'd rather connect a computer directly to a generator then have that UPS blow up due to improper voltage input, the UPS'es I'm talking about generally costs way above 600$...

[arneson]

Re: UPS problems with electrical generators

I would sacrifice a couple of UPS's for fun. We have no huricane threat so I would like to test the generatos anyway.
I have it just to keep the fridge cold for a few days. I would like to keep my modem and router up after a storm.
I would normally never connect an APC to a gen but I have installed on board inverters that run when the ships generator is fired up. They have large battery banks but the principle is the same.
I also install power sensetive equipment like sat receivers that can not stand bad power.
I've put together remote demo booths powered only by gens and operated big screen sonar and chartplotters all day with no problem. Ive also seen laptop power supplies melt down as soon as they were pluged into a semi sine wave inverter.
When I gas up the generator I'll post the results with a couple of small UPS's but I have a bad feeling about possable sizzle and smoke.

[Maxxarcade]

Re: UPS problems with electrical generators

I ran my old UPS (APC Back-UPS 500) from my cheap Homelite LR4400 generator for a while with no problems. Though some UPS's will probably object to the voltage and frequency fluctuations more.

I've done some stress testing to quite a few UPS's recently, since I had a bunch of untested units that I was replacing the batteries in. I ran them with a 1000 watt halogen light, and also a projection TV and Xbox. Then I simulated what my utility power does around here, by unplugging and plugging in the UPS several times in rapid succession while under full load.

All of the APC units I had were rock stable, especially the Smart-UPS 1250's. I did get my old Sola UPS to shut itself down by doing that a couple times though.

Now all my computers, network switches, cable modem and security cameras are connected to APC units, and every time the power goes out or flickers on and off 3-5 times, I just laugh and keep right on surfing the net. I'll never go without a UPS again.

[arneson]

Re: UPS problems with electrical generators

Managed to get the Coleman Powermate ultra 2500 running and connected an APC pro 650 to it.
Never came out of battery mode. Didn't hurt anything but could only stand the generator for about ten minutes.
So for me it did not work and now have a headache. That's as far as I'll go with it.
Just to add words of advice about running a gas powered gen., if your going to put it away as I do, you must drain and run it dry in order to start it years later.

Yes I was flushing out the carburator during huricane Wilma.

[nova]

Re: UPS problems with electrical generators

thanks guys! (for some reason i wasn't emailed when more people replied to this topic)

@Maxxarcade:
"i ran my old UPS (APC Back-UPS 500) from my cheap Homelite LR4400 generator for a while with no problems."

how many hours do you think it was running from the gen?

[Maxxarcade]

Re: UPS problems with electrical generators

I probably ran on the generator for about 45 minutes. If I had not let the generator warm up and stabilize for a while beforehand, I probably wouldn't have had as much luck. The only things I had connected to the generator were a 60 watt lamp and my computer.

I think that particular type of UPS does not care near as much about noise and frequency problems as newer units do. It just watches the voltage level and switches to battery mode if it goes too low or too high. One of these days I'll try it with my Smart-UPS 1250 and see what happens.