# 12VDC Power Supply and Diode



## splatz (May 23, 2015)

I have to supply power for some very expensive process cameras. I need a top quality regulated 12VDC DIN rail mount power supply. Made in USA if at all possible. I'd prefer something I can set up in parallel for redundancy but that's not really a must. 

Can anyone recommend a brand? 

These cameras have warnings about reverse polarity in the documentation. I am worried someone (including me) will accidentally cross wires and fry a camera, people don't agree about the color code for 12VDC like they do with line voltages. Is there maybe a good brand terminal block with a diode in it?


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## Peewee0413 (Oct 18, 2012)

I think I've seen once that Wago makes terminal blocks with diodes. I have a machine that uses Wago I/O, and have no complaints. 

Sent from my SM-G965U using Tapatalk


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## CoolWill (Jan 5, 2019)

Holy cripes... I just did something similar not too long ago. I used an Eaton PSG480R24RM
power supply and the Altec 5702.2 diode module. The diodes are rated up to 1 amp, but you could parallel a few because there's 8 per module. I like that power supply because it's adjustable. I bumped the output voltage up to compensate for the diode drop.


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## gnuuser (Jan 13, 2013)

this may suit your needs



https://www.amazon.com/SDR-120-12-D...=2025&creative=165953&creativeASIN=B005T8XR08


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## Going_Commando (Oct 1, 2011)

People use other than black for - and red for + on 12VDC?


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## splatz (May 23, 2015)

Going_Commando said:


> People use other than black for - and red for + on 12VDC?


I guess it's supposed to be red+ and white- if negative is grounded, white+ and black- if positive is grounded, red+ and black- if ungrounded. This is more nuance than some can abide and also some will just think it doesn't matter, like the speakers in their basement, and do whatever.


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## Southeast Power (Jan 18, 2009)

We used these a few times, I'm sure they were 12vdc.

https://www.plchardware.com/Product...KLc-zIRqHFbtGTogjrsbdV3tels8SDC0aAgtLEALw_wcB


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## bill39 (Sep 4, 2009)

https://www.phoenixcontact.com/onli...03-01-01/f63b5ba3-6203-4e3d-9a54-1dfd436785c3

Phoenix has what you need. You can also get a redundancy module to tie both P/S together. They are not cheap but very reliable.

I’m not sure about the diodes or why you would need them.


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## splatz (May 23, 2015)

bill39 said:


> https://www.phoenixcontact.com/onli...03-01-01/f63b5ba3-6203-4e3d-9a54-1dfd436785c3
> 
> Phoenix has what you need. You can also get a redundancy module to tie both P/S together. They are not cheap but very reliable.
> 
> I’m not sure about the diodes or why you would need them.


I bought the Phoenix last time I shopped. I am not sure where they were made, might have been somewhere you wouldn't guess, eastern European country? But Phoenix is a very good company to deal with as far as I can tell. 

The diodes are to kill the circuit if someone crosses wires and reverses polarity.


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## splatz (May 23, 2015)

gnuuser said:


> this may suit your needs
> 
> 
> 
> https://www.amazon.com/SDR-120-12-D...=2025&creative=165953&creativeASIN=B005T8XR08


I see the Meanwell brand comes up a lot when internet shopping - have you had good luck with them? 



Southeast Power said:


> We used these a few times, I'm sure they were 12vdc.
> 
> https://www.plchardware.com/Product...KLc-zIRqHFbtGTogjrsbdV3tels8SDC0aAgtLEALw_wcB


The AB are pricey but nobody can say you cut corners if you buy them ... are they made in USA?


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## splatz (May 23, 2015)

CoolWill said:


> Holy cripes... I just did something similar not too long ago. I used an Eaton PSG480R24RM
> power supply and the Altec 5702.2 diode module. The diodes are rated up to 1 amp, but you could parallel a few because there's 8 per module. I like that power supply because it's adjustable. I bumped the output voltage up to compensate for the diode drop.


I found these, 
3A :smile: 
made in Italy :vs_worry:

I have to measure current - I could see it going higher but 3A is probably going to do it. 

https://www.asi-ez.com/pix/doc/sf901-sf903_datasheet.pdf#view=fitv 










I did not know of this *diode drop* you speak of. I like the idea because I could probably compensate for voltage drop so the voltage is right on the money at the device.


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## Service Call (Jul 9, 2011)

splatz said:


> I see the Meanwell brand comes up a lot when internet shopping - have you had good luck with them?
> 
> 
> 
> ...




I’ve used Meanwell power supplies several times for DC and have not had a problem. 


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## CoolWill (Jan 5, 2019)

splatz said:


> I did not know of this *diode drop* you speak of. I like the idea because I could probably compensate for voltage drop so the voltage is right on the money at the device.


Diodes (and similar semiconductor devices) have an inherent voltage drop across them no matter what the load is. It's usually between 0.5 and 0.7 volts. Not usually a big deal for high voltage, but needs to be addressed when sensitive electronics operate on low voltage.


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## emtnut (Mar 1, 2015)

We used Xp Power DIN supplies in traffic cabinets.

They performed well, and in some tough environmental conditions. Dusty, and -20˚C to +40˚C

Spec sheet ... https://www.xppower.com/Portals/0/pdfs/SF_DNR05-60.pdf

**edit** adjustable output as well.

I would get a higher rated diode than 3A. If you're pushing close to that range for extended times, you creating a failure point IMO.
That, or use multiple diodes like OneCallWilly said :biggrin:


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## gnuuser (Jan 13, 2013)

splatz said:


> I see the Meanwell brand comes up a lot when internet shopping - have you had good luck with them?
> 
> we had some equipment installed at the plant that had them.
> never had any issues with them! and they were quite tolerant to power fluctuation as i recall


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## bill39 (Sep 4, 2009)

Going_Commando said:


> People use other than black for - and red for + on 12VDC?


Unfortunately, yes.

NFPA-79 and I believe UL-508A both require blue for DC circuits. If the negative is grounded then it’s white w/blue stripe.


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## splatz (May 23, 2015)

So after thinking a little more about the adjustable power supplies. 

I'll have to install a separate power supply, diode, and pair of wires for each device. That way I can adjust the voltage on each power supply to accommodate for voltage drop in the diode and the wire. 

Any ideas for this: I don't want to make the adjustment with the expensive device, I want to connect the expensive device once the power supply is adjusted. To do this I will need some dummy load to match the device. So the dummy load will have to be something I can adjust so it matches the actual device. I haven't yet measured but based on the factory 12V 2.5A power supply, the device will draw less than 30W.


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## JRaef (Mar 23, 2009)

The only DIN rail mount industrial power supply I know of that is still made in the USA is Acopian.
https://www.acopian.com/DINrailmountable.html#AC-DC-Single-Output-DIN-Rail-Power-Supplies
Small company, not well known, not the low price leaders but the products are decent. 



Pretty much everything else comes from the same 5 Asian suppliers; Puls, Meanwell, Chint, Delta and Idec, but most of the other brands that you see (such as Phoenix, A-B, Siemens, Power One, Eaton, Sola etc. etc.) are almost all just brand-label deals with one of these 5 Asian suppliers. Meanwell is a latecomer to the party and commands attention because they are cheap, I have had many people complain about them. They (and Chint, Delta and Idec) get cheaper by cutting corners on the magnetics inside of the PSU, so they put in a "fold-back" circuit to take it off line if there is a surge in demand on the output side. That pisses people off when it happens. Puls (who makes the Allen Bradley and Siemens products) don't do that, they have surge capacity built-in. Still made in Asia though, even though Puls is a German company.


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## ppsh (Jan 2, 2014)

I believe the Siemens SITOP lineup is Austrian or Romanian made depending on the series.


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## CoolWill (Jan 5, 2019)

splatz said:


> So after thinking a little more about the adjustable power supplies.
> 
> I'll have to install a separate power supply, diode, and pair of wires for each device. That way I can adjust the voltage on each power supply to accommodate for voltage drop in the diode and the wire.
> 
> Any ideas for this: I don't want to make the adjustment with the expensive device, I want to connect the expensive device once the power supply is adjusted. To do this I will need some dummy load to match the device. So the dummy load will have to be something I can adjust so it matches the actual device. I haven't yet measured but based on the factory 12V 2.5A power supply, the device will draw less than 30W.


Rheostat? Multiple incandescent brake lamps?


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## Florida (Nov 20, 2018)

*Sola*

Not sure about the made in usa, but we have had great success with 24vdc sola power supplies and ups.

looks like they are part of emerson and appleton.


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## emtnut (Mar 1, 2015)

splatz said:


> I'll have to install a separate power supply, diode, and pair of wires for each device. That way I can adjust the voltage on each power supply to accommodate for voltage drop in the diode and the wire.
> 
> Any ideas for this: I don't want to make the adjustment with the expensive device, I want to connect the expensive device once the power supply is adjusted. To do this I will need some dummy load to match the device. So the dummy load will have to be something I can adjust so it matches the actual device. I haven't yet measured but based on the factory 12V 2.5A power supply, the device will draw less than 30W.


I would look up the specs for the camera, and just do a voltage drop calculation based on the spec amps. Add 0.8V for the diode (the drop is current dependent, but doesn't change much.. from what I've seen). You could look up the curve for your diode if you want thou.

You should be able to calculate within .2V I would think.


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## splatz (May 23, 2015)

I still haven't finished this project. The Phoenix power supplies are good quality as far as I can tell but a little big, they have other models that would have fit the enclosure better. Adjusting for voltage drop was simple and easy. 



I also bought the Phoenix Contact DIN rail diodes and they are good, just as advertised. However, it occurred to me that some cross-ups you'd be safer with the diode closer to the camera. The DIN rail diodes are pretty big and hard to work with in the enclosure by the camera. 

I found these beauties which I will be swapping in











http://eco-energy.us/diodes/diodes.html


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## CoolWill (Jan 5, 2019)

splatz said:


> I still haven't finished this project. The Phoenix power supplies are good quality as far as I can tell but a little big, they have other models that would have fit the enclosure better. Adjusting for voltage drop was simple and easy.
> 
> 
> 
> ...


That's cool. They are Schottky diodes too, so the voltage drop across them will be lower than standard diodes.


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