[rescue] UPS rescue, now what?

[Greg A. Woods]

[ On Tuesday, July 30, 2002 at 21:24:35 (-0700), Koyote wrote: ]
> Subject: [rescue] UPS rescue, now what?
>
> Okey, so I got the 2 UPS units from Hades. all 360 pounds of them.

Telling us the combined weight of the units doesn't help much here.

What's the exact manufacturers name and model number?  (I.e. type in the
identification and ratings label on the back of one of the units!)

> the input and output of these units is 220/240/250. No sweat, most any
> PS takes 240- the output is not a problem

True, but you'd better be careful.  To do this properly you'd have to
change all your power bars and power plugs so that you don't make the
mistake of accidentally plugging in anything still set to (or only rated
for) 120vac.

Also your insurance will probably be null and void if you don't make all
your wiring between the UPS units and your computers conform to the NEC....
(i.e. change all your plugs and cords)

> I simply have to use a step up transformer to power these puppies
> (okay,t o power *one*, at least for now) and I need to figure out the
> plan. I mean, I'm not going to try and use a 250watt transformer,
> here. But I'm a bit lost on whether I need a 1kw or a 2kw or what?
> the thing I can say for sure is that I have some 10A fuses onboard,
> and the *outlet* for the power in is rated 16A at 250V (not the
> *unit*, the outlet)

Ah, no, you're absolutely going to have to supply it with full 240vac.
If it can push 16A at 240vac then it's going to pull at least 20A, maybe
30A.  First off there's the battery charger circuit which must run while
the unit can deliver full rated power, and then there's the efficiency
factor (my biger 3.1kva BEST FerrUPS units are rated at only 91%
efficiency at full load, so they themselves burn at least 9% more than
the load they're pushing out.

You cannot "legally" have a 120vac circut rated at more than 15A without
special wiring and plugs and it's going to only give you about 12A for
real, so even firing up the battery chargers on those things may blow
the breaker if you try to hook them into a step-up transformer.  The
step-up transformer will itself burn some watts too!

> I'm having a real hard time tracking down more numbers on this, but
> assuming I can run this on a 100 res circuit at all, how much do I
> absolutely have to buy in a transformer?

You absolutely have to run a 220vac circuit, and as to whether or not
you'll be able to run it on a 100A service depends on what else is
already running on that 100A service.

Your insurance will also be null and void if all the wiring between your
electric meter and the UPS units doesn't also conform to the NEC....

Call a licensed reputable electrician and have your UPS units hooked up
properly.

-- 
								Greg A. Woods

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