You can use the 24V variant of this style of open frame PSU (VOF-300-24)with the HDPlex and KMPKT DC-DC boards. Should you choose to go with a 12V solution (VOF-300-12) you can use them with the G-unique units.
As far as no active cooling, if you take a look at the
specification sheet you will see two ratings for this unit. One is convection cooled (200W) and one for actively cooled with 10 CFM of airflow (300W). In other words, to get the full 300W out of the unit safely you will need a minimum of 10 CFM of constant airflow over the board in accordance with specification (ie. they will specify how much airflow you need from each direction in order to cool this unit).
I will mention that this unit is very expensive for what it is (
122 USD) and that you would likely be better off going for a
Meanwell EPP-400-24 unit. Going with this model will cost about half as much while having a significantly higher power output (
69 USD). The tradeoffs are that the Meanwell is 0.5% less efficient and has a ripple of 200 Vp-p. The CUI only has a ripple of 150 Vp-p. The DC-DC supply
should smooth this out to within ATX spec (less than 100 Vp-p), but I can't make any guarantees for my own units not anyone else's (ie. use this style of unit at your own risk). The Meanwell unit provides 250W with no cooling and up to 400W with 25 CFM of air (and likely a shade more than the CUI unit at 10 CFM) while remaining in the same footprint.
Also worth mentioning at just a hair above 1.5" (40 or 41mm) are the HDPlex AC-DC units which you can find here:
HDPlex 160W AC-DC (200W Peak)
HDPlex 300W AC-DC (400W Peak)
