How to Make a 24VDC Power Supply into a Redundant System.

[@RadDadisRad]

I had a power supply voltage regulator go out and spike my control power to 33V. I’m so grateful that so many devices have such a wide tolerance of input voltage.

[@TimWilborne]

Yes, thank goodness!

[@canadajim]

Some projects connect each 24VDC source to a common DC rail, via a diode (on each source). You can connect as many sources as you want that way.

[@TimWilborne]

That still isn't redundancy

[@PaulR387]

I never knew about the redundancy module, great stuff, Thanks for sharing this..

[@TimWilborne]

Glad to help!

[@Isaac-qd6gy]

Couldn't you accomplish the same thing with a simple relay? Have the 24VDC of one power supply run to the coil of a relay and the 24VDC of the other power supply run through the NC contact of that relay? If it was a DPDT relay, the other set of contacts could go to a PLC input for an alarm.

[@TimWilborne]

That would only cover a 100% failure and you would still have a momentary dip in the 24VDC during the relay switching. The diode method would be more reliable. courses.twcontrols.com/courses/take/ul-508a-industrial-control-panel-course/texts/50068633-diodes-on-paralleled-power-supplies-to-make-a-redundant-system

[@mickyfranks]

So what happens if the redundancy module fails?

[@TimWilborne]

Great question Micky. There are two version of it. There is the ORING which is the setup we showed in this video then there is the S ORING which we ran out of time before we could discuss. It eliminates that single point failure by adding redundancy to the redundancy module.

[@HuntingtonBuilt]

Awesome!

[@TimWilborne]

Thanks!

[@inothome]

What's wrong with just using a diode in this DC example laid out in the video? Aside from the alarming outputs this paralleling module may have.

[@TimWilborne]

Lots, that isn't redundancy.

[@inothome]

@@TimWilborne Not to argue, I'm genuinely curious as to how this module is better than a diode in DC applications? This module appears to have two inputs and can have one output. If this module dies, is it fail safe and will still pass current? Seems a single point of failure, as opposed to multiple DC power supplies being protected by diodes. Where you can have the two power supplies feed different ends, for example, high voltage switch gear where you can have two totally independent DC power supplies (batteries, charger, PS etc...) that relies on a passive component to isolate one or the other if one source fails. I am not against this module, I just don't see the benefits to it vs simple diodes. I guess I should go do some research on it as well, curious......

[@inothome]

I love Phoenix Contact equipment, but even after looking over documentation on the module I still think a diode is much better in DC applications. And I didn't see any AC modules. Just seems like more to go wrong and a way to over-complicate a simple function. Anyway, keep up with the videos, I thoroughly enjoy them.

[@TimWilborne]

That is a great question. It is always a balance between the cost of the system up front and the cost when the system fails. Here are a few pros and cons Pro of diodes: Cheap Cons of diodes: Voltage drop of ~0.7Vdc Good deal of heat loss with larger power supply systems. Manually have to balance voltage Regular maintenance to check power source voltage drift Pros of Mosfet redundancy: 70% more efficient than standard power diodes Active load balancing (equal share of current from both power sources) Cooler power supplies last longer No need to balance power supplies during commissioning Feedback on total system current Feedback on status of redundancy and input voltage Con of the “OR-ing” module Single point of failure but their S ORING solution even solves that.

[@inothome]

@@TimWilborne Some good points there, agreed on higher power applications the power loss across the diode. I didn't see how the redundancy module pulls from both PS, cool if it does. I just happened to notice when you killed one the voltage dropped and when you restored it, it didn't swap right back to the higher voltage. Both have their advantages, I still prefer the diodes due to less to go wrong. Maybe in a higher power application I would try the redundancy module. Anyway, great video and thanks for the answers.

[@davem5392]

What is the negative consequence of running them in parallel if one fails. Would your system still work but you just lack an alarm on broken ps

[@TimWilborne]

In the one case I did it, when one power supply failed, the other failed right behind it.

[@dennisrubio2375]

Excelente

[@TimWilborne]

Gracias

[@jamesmcdaniel920]

I have no sound

[@TimWilborne]

Check your mute button