Re: HMC Question -- MIDRANGE-L

UPS' have ratings of vA (volt-amps). These seem similar to watts - remember PIE (Ohm's Law)? P = I x E (P = power in watts, I = current in amps, E = voltage in volts). It may not be completely accurate, but I find the load for each unit attached to the UPS - it's usually on a label in back. Add'm up. You probably want to worry about peak vs. average. I'm sure others have more info, and the manuals (perish the thought of RTFM) have guidelines for all this.

HTH
Vern

At 09:01 AM 8/19/2004, you wrote:

midrange-l-bounces@xxxxxxxxxxxx wrote on 08/18/2004 08:36:31 PM:

>
> >We will probably just put our existing UPS's on top of the rack to
power
> >the xSeries and keep it simple.
> >
>     Um, UPSs on TOP of a 7 ft rack?  That sounds slightly dangerous to
> me but it's not my computer room!!

These UPSs are rather small, although of course they are heavy.  The rack
is so big, it doesn't seem much more dangerous than having them on a
shelf, other than that they are higher.  We might put them on the floor
behind the rack.

>
>     One other thing, don't plug one UPS into another UPS. This is easy
> to do when you have several small ones but is very bad for the UPS
> that's getting doubled up on!  One of our customers had this setup and
> wondered why 'that big AS/400 UPS never EVER lasts as long as all the
> ones for the NT and other servers. What gives?'  You can guess
> why.....

We didn't plan on doing this, but I get the point.

> Also each UPS needs it's own circuit from the panel.  Them
> darn things draw a BUNCHFULL more power after an outage (to charge the
> batteries while still carrying the load)  and of course that's when
> you'd trip the breakers when there is more than one on a circuit (and
> coincidentally when you need it most!)

Very good point.  Worth checking into.  One of the reasons we wanted to
somehow utilize the iSeries UPS, is that we had to run a dedicated 220
circuit for it and that was the last circuit available in our panel.  Of
course, we already have some other ones in the computer room we have
already been using, but it would be nice to utilize that 220 circuit and
UPS if possible.  How do you go about figuring out how much a single UPS
can handle?  We are mainly interested in surviving power hiccups.

Mark

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