UPS and generator interaction?

Tue Mar 30 00:14:08 UTC 2004

I had trouble like this years ago.  Seems that some UPSes only recognize
sine-wave AC power, whereas some UPSes provice something more like
sawtooth or square-wave AC power.

Inserting a Variac (very inefficient) between the generator and the
sensitive UPSes fixed the problem.

Dave Hilton
SysAdmin
Entelos

Dum Spiro, Spero

-----Original Message-----
From: Mike Lewinski [mailto:mike at rockynet.com] 
Sent: Monday, March 29, 2004 10:54 AM
To: Brian (nanog-list)
Cc: nanog at merit.edu
Subject: Re: UPS and generator interaction?

Brian (nanog-list) wrote:

> Does anyone know of a way to get a UPS to trigger a generator to 
> start, and to switch over to the generator power automatically or does

> this type of thing just not exist?

What Patrick said.

But, on a minor note that probably won't affect your Symmetra but I'm 
posting in case anyone else here can shed light on.... we had a power 
event this AM. The transfer switch did it's magic and all was good... 
Except for two new APC1400's- they failed once the batteries drained. I 
triple-checked that they were on the right panel, played with 
sensitivity, even tried daisy-chaining one off a good working 2200. 
Nothing I did would convince the two 1400s they had power. Once the 
house power was restored they came back to life and look normal. I later

learned that two of our colo customers with APC1400s had the same 
problem :( Other models (even a couple non-essential lower-end, dumb APC

450s and 650s) didn't blink at the generator power.

Mike