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Subject: Re: [motm] For all the woodchucks out there

From: "J. Larry Hendry" <jlarryh@...>
Date: 2000-08-07

----- Original Message -----
> From: <jwbarlow@...>
> Larry had a great idea (if one of the 900s was enclosed
> with a different front panel) using a female IEC connector
> and wiring the AC of one module so that one 900 turned
> on both PSUs.

Well, that was a slightly different discussion on a nice way to possibly
integrate multiple 900s. However, since I don't own a 900 and have the 900
docs, I can't really give informed advice.

> I remember Gene Stopp on the diy list suggesting that it was
> well worth it to run PSUs at about 50% of their rating.

I can offer my opinion in this. I think that approach is a bit
conservative. However, leaving head room is a good idea. I plan to load my
supplies based more on how many modules are in "that" particular cabinet.
However, in all cases, I will probably draw the line at about 80% of

As a point of interest, I would like to point out how your local power
company determines the loadability of transformers and power lines. The
"nameplates" are just guidelines. The industry standard is to operate the
transformer up to the maximum load that will not get the transformer any
hotter than XXX degrees C. Everybody uses different numbers for that limit,
but it is ALWAYS well above the nameplate. Power line loading is based on
sag in the wire (no sh∗t). The loadabiliy of the line is based on the
physical clearance between the wire and whatever is below it (or the
clearance to ground code). Normally, that is in the 80 to 100 degrees C

Disclaimer: Do not use these methods at home. We are trained
professionals. :)

Larry (I often refer to 12.5 KV as the "low voltage" stuff) Hendry