Hi!

Now you mention it, it hadn't occurred to me either. There is usually
one or more extractor fans in the top of the system cabinets to remove
heat generated by the multitude of contactors and inverters !

This was set up in such a way that the contactor was mounted inside the part
where the interior air circulation fan goes. It would benefit from the air
flowing by to meet the fan and get pushed through the registers in the
house.

It was easy to do, so I also went out and had a look at the contactor used
on my central air conditioner. Couple of screws and one small metal panel
later, I saw pretty much the same unit as the one I'm using for this other
project. And it can't get much, if any cooling air where it is situated. The
makers chose to put it in a relatively weather-but-also-air tight box. It's
run for 14 air conditioning seasons now...so the designers must not have
done too badly.

That seems about right for a small single phase contactor.

Small, but with two sets of switched contacts. It could be used to switch
both the hot and neutral portions of the line, but I suspect that it
actually switched two 120 volt hot lines in the original application. (The
original unit is no longer around now for me to check.)

You could always use a salvaged PC PSU fan to provide an airflow !

I thought about doing that, but I don't want to precipitate a fire if one
should ever occur. Nor do I want the dust buildup in the box that all this
stuff is going to be put inside. I have noticed that when bolted to a metal
plate, that the contactor sheds heat through it. It would be easy to work
that into what I'm doing.

Thank you for all your help and information so far.

William