ATX Power Supplies - What do I REALLY need?

Good information there. I thank you for it.

Yes, I am using fans to ventilate and cool the pendant. Intake is a 5" fan blowing directly on the processor and outtake is the power supply fan. Filter on the intake. This is how it sits right now. LCD, MPG, and hard button switches will be installed in the cover this weekend. I need to cut an access panel for the 5i25 cable to run from here to the control cabinet and 7i77.

When possible I do not ventilate such an enclosure with external air at all. Filters get dirty and filter only 90% or so, in the winter there is a high level of humidity (in my garage, that is), etcetera.
Quite often just circulating the air inside so heat is transferred to the enclosure sheet metal is sufficient; after all the enclosure features a huge surface area which doubles nicely as heat exchange. This way the delicate electronics are totally separated from the evil outside.

200MW by itself says nothing, that's just a huge number. If you can have plenty of heat exchange surface area, plenty of passing fluid and maybe a high delta-T is allowed then it's just upscaling. Although I doubt anything in aerospace is that simple

I used to be into overclocking PC processors: >1MW/m2 heat flux, and that got transferred to the coolant (boiling ethylene at -110C) with a 6K difference between chip and coolant temperature. That took a bit of very careful preparation of evaporator and chip surface

But back on topic: I used to run a Celeron G550/Z77 mainboard/harddisk/MESA 5i25/powersupply/etc. in a small minitower with all the holes in the enclosure taped off. A 120mm/7 Watts fan was used to circulate the air in the enclosure and over the bare PSU. Result: inside temperature was about 12 degrees C warmer than the outside. Very acceptable.

My current mill-to-be needs ventilation, unfortunately. I tried it with approx 2,25 square meters of sheet steel as heat exchange area, but all the servo drives, VFD running at a high switching frequency, PC, power supplies, spindle cooliing, etc. produces more heat than I can get rid of without active ventilation.

DaBit wrote:

When possible I do not ventilate such an enclosure with external air at all. Filters get dirty and filter only 90% or so, in the winter there is a high level of humidity (in my garage, that is), etcetera.
Quite often just circulating the air inside so heat is transferred to the enclosure sheet metal is sufficient; after all the enclosure features a huge surface area which doubles nicely as heat exchange. This way the delicate electronics are totally separated from the evil outside.

I gave this a bit of thought and decided to move forward with ventilating it. I'm gonna have a bit of heat generating bits in there and the shop is air conditioned so I'm going to err on the side of caution. Besides, I actually do maintain the machines and controllers, so do open them up and clean and dust a few times a year. Even the oldest of them all has never had much inside it.

A few progress pics while I'm still awaiting power supply extensions.