generator & UPS

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mhayes

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I recently installed a 30 kw generator at a veterinary clinic without the knowledge of how many computers where being used with individual UPS systems. There ends up being about 25 and also 1 for the server. Upon transfer to generator power, all the selected lighting and heating works fine, however, none of the UPS systems will transfer off battery to generator power. We tried unplugging all but 5 and still could not get any to transfer. We then unplugged all and still couldn't get the server UPS to transfer. Other than installing a larger generator (more commercial) is there any other remedies to fix this situation?

Thanks, Mike H
 
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zbang

Senior Member
Location
Roughly 5346 miles from Earls Court
I'd start by checking the generator frequency & voltage? Both with and w/o load.

What UPS are they? Are they $1.95 units from the local junkyard or something like APC SmartUPS/Leibert (or similar).

Also, if there are 25 small UPSs, might be better to replace them with 5-7 larger ones.
 
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betcher78

Member
An issue I had when we started hosting racked server euqipment for India customers here in the US, was this exact same thing. We had 2 - 120v, 30am twist lock UPS units. We did think of testing before an outage condition happened, but it still bugged us for a week or so.

To test my theroy we plugged in a small heater into each side of the 240 feed we had coming from the roof.

This seemed to put a more constant load onto the genset. we did also find out however , after the generator was running for about 15 mins. The problem with the UPS's would also go away.

We did not have a perm install setup. It was a 17K wheel unit up on roof. for temp use. So there was not any adjustment of the freq, and or voltage output. we learned we could just wait , UPS would last for about 3 hours anyway. so 15-20 mins before they would switch over to generator was fine in our case. This can definatly be very agrivating to say the least.. Any way to test with genset disco from building transfer? make sure to have a constant load- like a couple of heaters. ?
Good luck
 
ron

ron

Senior Member
Location
New York, 40.7514,-73.9925
Mhayes,
So the UPS's never recognize the generator as a good source?
You need a good meter to be sure the gen has a clean output.
It is unlikely that the cheap single computer UPS's are sending harmonicas upstream to screw with the generators voltage regulator, so I think the generator may have a bad output.
Does this gen have a solid state voltage regulator?
What are the output harmonics without load and with resistive load only? That will help you troubleshoot.
 
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