[TowerTalk] OT: Generators and UPS's

Doug Rehman rehman at surveil.com
Fri Aug 25 10:11:22 EDT 2006

Thanks to all for the replies.

I did leave out another link to TowerTalk: the generator powers the tower
lights when the grid is down...

To answer a few questions and make a few clarifications:

The line conditioners are true line conditioners; They are APC model Line-R
600. They do a great job during the occasional low voltage episode. About
once a week or so, they'll kick in and raise a low line voltage from the

I don't have a problem with the UPS's during normal operation from the grid,
only when off-grid and running on the back up generator.

One of the units that died from cycling during this week's grid outage is a
one week old APC 500 VA model, so I don't think the cycling is related to
the battery condition- just the noise from the generator as compared to the

I do have a whole house surge protector installed. It doesn't seem to do
anything for the generator's noise though.

There were some suggestions about replacing the UPS batteries with larger
ones (such as marine deep cycle). While it would greatly extend the runtime
of the UPS's, I only need the UPS's to run for the 30 seconds it takes for
the generator to come on line. The primary purpose for the generator is to
power everything during prolonged outages such as the 5 day one during the
2004 hurricane season. (I'm in Central Florida.)

After thinking about it a bit, the UPS's that were not cycling were all
lightly loaded. (The Belden on the phone system was one of the ones that
didn't cycle- I doubt the phone system, an NEC DS1000, draws more than an
amp or so. An APC 500 VA on the shack computer was another that didn't
cycle- the computer was turned off.)

Perhaps the solution lies in using over-sized UPS's?


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