no cooling fan

[plastics]

I noticed that there is no cooling fan on the control box (big aluminum part) when I opened it seemed really warm.

[Gary Campbell]

Justin...
The control box is designed to act as a heat sink and dissapate heat thru the fins at the rear. Having a sealed box keeps dust out. IF you are experiencing extraordinarily high ambient temps, set a box fan to blow on the rear of the box.

[plastics]

ok, except that there are no fins in the rear, only wire ports.

[Gary Campbell]

Justin...
My bad... only the alpha has the cooling fins. Is yours a standard?

[plastics]

i assume so, it was purchased in 04 its the PRT alpha 96.

[Acmeaviator]

I think any system that uses PCM runs hot due to the heat generated when the system is receiving power but the motors are not consuming it. I run PCM model trains and they have little heat sinks inside the housings to radiate the heat when they are at rest. It freaked me out at first until I realized that power has to go someplace.

[paul_z]

If my memory serves me (and it often doesn't), I believe the first alpha control boxes did not have fins. I'd still direct a fan at the control box; it will help a lot.

You might consider glueing on vertical fins. Although the thermal resistance of the glue is high, it is thin and would have a rather large area.

Paul Z

[ken_rychlik]

If you call shopbot you may be able to buy the fins and bolt them to the outside of the box behind the drivers. That would help, but I would still just direct and external fan toward it.