Parallel 24V DC power supply for control panel? Possible?

[rsdoran]

Not sure what you are asking. The unit you linked to is a redundancy module i.e. you can connect 2 power supplies to it and have one output, if either power supply fails the associated relay will drop out. No need to add diodes, they are incorporated as shown in this pic.

 

[flyers]

Not sure what you are asking. The unit you linked to is a redundancy module i.e. you can connect 2 power supplies to it and have one output, if either power supply fails the associated relay will drop out. No need to add diodes, they are incorporated as shown in this pic.

Sorry my mistake, I taught this DR-RDN20 required two units to do redundant feature. It's actually a unit with built-in DIODE for redundancy feature. I can use 2 normal meanwell power supply and connect a diode & relay (for alarm) in each output to do the same job, but it's not a proper method.
So I think we'll have to settle with the common model, S-320-24 http://www.meanwell.com/search/S-320/default.htm .

Below is my design, any comments from you guys?

 

[BobB]

I can use 2 normal meanwell power supply and connect a diode & relay (for alarm) in each output to do the same job, but it's not a proper method.

Why? I do it all the time - it works and is very reliable. Probably a lot more inexspensive also. Have not seen the Meanwell units in Ozz at all.

 

[Calistodwt]

You can either make up your own diode blocking units or else use the simpler option and purchase the redundancy module DR-RDN20 which is essentially a diode blocking unit. On your proposed system you will have redundancy for power supply failure only, which is ok if you are not concerned with the mains power failure for which you have no redundancy. If redundancy is required on mains power then install a small UPS on one ofthe supplies.

 

[pw3]

Moore Industries makes a dual/redundant 24vdc power supply, I believe rated up to 3A. It uses two conventional xfmr/cap type circuits (versus switching) and has alarm contacts. They cost about $700e and are very stoutly made. If this is of interest to you I can locate the p/n as I don't believe they list this model on their website.

Also, Phoenix Contact makes a din-mounted diode block (as described in previous blogs) specifically for connecting two DC supplies in a parallel/redundant config.

 

[flyers]

Moore Industries makes a dual/redundant 24vdc power supply, I believe rated up to 3A. It uses two conventional xfmr/cap type circuits (versus switching) and has alarm contacts. They cost about $700e and are very stoutly made. If this is of interest to you I can locate the p/n as I don't believe they list this model on their website.

Also, Phoenix Contact makes a din-mounted diode block (as described in previous blogs) specifically for connecting two DC supplies in a parallel/redundant config.

Hi,

Meanwell has a din mounted diode block as well, the DR-RDN20 is a 20A diode block by meanwell. Other option is using a 3rd party diode, i'm using SKKE 81/08 diode.

BTW, does anyone know how to check the efficiency or power factor of this diode?
http://www.semikron.com/internet/ds.jsp?file=800.html

Thanks a lot.

 

[Alan Case]

Hi Bob.
Meanwell power supplies are here. I see quite a few of them. Quite a good little unit.
Regards Alan Case

 

[fayaz ps]

hi

i need a star delta starter logic diagram

Hi guys,

I'm designing a control panel system and one of the require from customer is to have parallel (2 units) power supply (24V DC) for the control panel & PLC as well.

There is one incoming 230V AC to the 2 units of power supply (230V AC to 24V DC). Each 24V DC power supply output will energize a relay & a pilot lamp (24V DC). in the event if any of the 24V DC power supply is faulted the relay wiil be de-energize and send an OFF signal to the PLC DI and the pilot lamp for that particular power supply will also be OFF.

My concern is do we need to put a diode after the power supply output, after the relay & pilot lamp so there is no current flow backward? Or izzit possible/advisible to do so?

I'm not sure what problem will I be facing, please advise me....thanks a lot.

 

[thanhbinhvtvn]

Hi Flyer,
What type of diodes you choose for redundant parallel power supply and their technical data (rating current, voltage etc.)

 

[iant]

Welcome to the Site.
This is a very old Post 2007
Diode current ratings and Voltages are dependent on your requirements.
I would recommend that you consider the total line current as should one fail the other supply needs to supply twice the load.
the only other consideration is the dissipation of heat.

 

[John Gaunt]

Yes this is a very old post but following this post we now use Meanwell diode units rather than building our own diode unit.
We sometimes use others but mostly use the Meanwell power supplies also.

 

[BobB]

I use a standard bridge rectifier for combining the battery supplies - usually 40 amp as they have metal cases. I then use Meanwell 24/24VDC power supplies to feed the PLC etcetera. I do not groung the negative output from the switch modes but let the 24VDC float - maintains isolation that way.