Redundant 5VDC power supplies


Has anyone ever had the need to have redundant 5VDC power for an Opto Rack? I’ve used QUINT DIODES from Phoenix Contact on 24VDC supplies, but I need to locate something for 5VDC.

Are Opto 5VDC supplies capable of being paralleled without diodes? Not sure what the failure modes would be if one of the supplies failed.

Any help would be appreciated.


Couldn’t you just use the fault/fail relay contact that is built into some supplies? Or I think ABB makes some that can be hooked up parallel as a slave/master setup.
I’ve never really thought about a PS failure. They are cheap enough that I just stock one on the shelf here and it’s a max 5 min. swap if it ever happened.
In your current setup, how do you know if one fails?


I have never had a SNAP PS5U fail in the shorted mode, which is what might cause the most problems.
I have had one fail open out of 100’s installed.
I haven’t seen a schematic of the Opto 22 PS though so not sure if there might be other issues. We have used both 5 & 24vdc in parallel without issues. If you use diodes you may want to use a remote sensing supply because of how picky 5vdc PAC’s are about low voltages (I know you know that, but in case someone else reads this,)