Re: mainboard that seems good for some possible EMC developments

[jmkasunich-at-ra.rockwell.com]

> > only has a tiny processor fan, so it could be mounted in a
> > sealed dust-tight box with heat exchange fins on it to conduct
> > away the heat stirred up by the tiny internal fan...

> interesting solution.

> why could the ATX power supply not also be inside the sealed
> metal box?

> Should work with a low power motherboard and perhaps another
> (dirty) fan outside keeping the case

Some possibly useful info:

I design industrial VFDs for a living.  On the other side of the
office is a group that packages VFDs and other equipment, sometimes
in sealed enclosures.  Their rule of thumb for a sealed enclosure
is 1/8 watt per square inch of enclosure vertical surface area.
This means front, back, and sides - heat transfer from the top and
bottom are much lower because there isn't much air circulation
around horizontal surfaces.  Don't count the back if the enclosure
will be mounted on a wall.  This will result in approximately 15
degrees C temperature rise inside the cabinet.  A circulating fan
inside the cabinet may improve it by about 10%.  The rule of thumb
is only valid for steel cabinets.  Plastic will be worse, aluminum
might be a little better.

For a tower computer case, 24" high x 16" deep x 7" wide, this
works out to 1104 square inches, and 138 watts for a 15 deg C rise.

Another more detailed source for this info is the technical info
web pages published by Hoffman - they make industrial enclosures.

The index page is:
http://www.hoffmanonline.com/Technical_Info/
thermal info is near the bottom left.

One specific page is:
http://www.hoffmanonline.com/PDFCatalog/SpecifiersGuide/A-DAppendicesPDF/Aheatdis.pdf

John Kasunich