UPS

[Chip Rosenthal]

In article <1991May21.070537.15809 at rfengr.com>
	rfarris at rfengr.com (Rick Farris) writes:
>I want to have an hour's worth of UPS capacity.

What are you going to be doing for that hour while all the printers
and terminals lie dead waiting for power to return?

It's your money - but unless you've got unusual conditions, 99% of
all power failures (SWAG statistics) are going to be measured on the
order of milliseconds.  I don't want any more then ten minutes of
capacity from the UPS - if power isn't back in five minutes then it's
time to do a shutdown.

A UPS which keeps things running for extremely long durations of time
isn't of interest to me.  What I'd find important is a UPS which isn't
too impatient about returning back on-line.  You can get some real
crap coming through - and some false starts - when power returns.  I
think it's critical that a UPS takes its time and ensures power is
solid and stable before giving the green light.

I've been using Unison UPS's.  They are pretty inexpensive for a true
UPS, and seem to do the trick.  They've got a port I can monitor
through a serial line and effect an automatic shutdown.  Unfortunately,
they use a DIN connector instead of something easier to work with
(e.g. a DB).  Also, they use that dorky flat profile box, so the thing
is supposed to to be able to sit on a peecee.  I've only been using
them for about six months, so I don't know how they are on battery
life and cost/hassle of battery replacement.  I home I'm not in for
any rude surprises.

I've heard good things about Clary supplies.  People also seem to say
nice things about the Best supplies.  Although the Best isn't a true
UPS they are reputed to have very good ferromagnetic filtering.
Myself, I'm lusting after a Toshiba 1KVA unit - but damn they are
expensive.  The spring storm season seems to have passed, so I think
I can afford another six months of waffling.
-- 
Chip Rosenthal     <chip at chinacat.Unicom.COM>  |  Don't play so
Unicom Systems Development      512-482-8260   |    loud, Mr. Collins.