Quote Originally Posted by Ioannis View Post
... PWM may stuck in the ON state and burn everything...

That is my biggest concern with this plan.


My design now has 3 enclosures, with power being fed into the center unit. I'm now thinking of using 3 separate voltage regulators; one per unit.

That way each 7805 doesn't get as hot as a single device trying to feed all three. Less complicated (less parts, simpler circuitry) than trying to "cheat the system" so to speak.