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Thread: Phoenix Contact Redundancy module

  1. #1
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    Phoenix Contact Redundancy module

    Hi everyone, this is my first question on here.
    I came across an electrical panel recently that had the following redundancy module installed in it: https://www.phoenixcontact.com/onlin...ary=usen&tab=1

    I am trying to look at the block diagram to try and understand its functionality.
    Is the diagram saying that if I connect two 24VDC 10A sources on terminals In1+ and In2+, I should get the same 10A in the two '+' terminals?
    Also, what is the purpose of terminals 13 and 14 in the block diagram?

    -RJ

  2. #2
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    It is, as shown in the block schematic, essentially a two diode OR circuit that combines the two inputs to drive the output without allowing one supply that fails to a low voltage to pull down the other supply.
    The two contacts, 13 and 14, provide an isolated (floating) dry contact closure that indicates that one of the two inputs is no longer working properly (output gone or voltage too low.)
    The only difference between this module and a simple two diode bridge is the monitoring circuit.

    You can combine two 10A inputs to provide 20A output, but falling back to 10A when one module fails or you can use it to combine two 10A inputs to one 10A output which will still be present after one of the two supplies fails.

  3. #3
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    Basically a Quint diode. Fail safe 24vdc.

  4. #4
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    Quote Originally Posted by charlie k. View Post
    Basically a Quint diode. Fail safe 24vdc.
    Any idea why a unit with (functionally) two diodes is called a Quint diode?

    Sent from my XT1585 using Tapatalk

  5. #5
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    Quote Originally Posted by GoldDigger View Post
    It is, as shown in the block schematic, essentially a two diode OR circuit that combines the two inputs to drive the output without allowing one supply that fails to a low voltage to pull down the other supply.
    The two contacts, 13 and 14, provide an isolated (floating) dry contact closure that indicates that one of the two inputs is no longer working properly (output gone or voltage too low.)
    The only difference between this module and a simple two diode bridge is the monitoring circuit.

    You can combine two 10A inputs to provide 20A output, but falling back to 10A when one module fails or you can use it to combine two 10A inputs to one 10A output which will still be present after one of the two supplies fails.
    Thanks GoldDigger for that explanation. I think i understand now. The way I see it wired in the enclosure in front of me is that it 2 10A inputs are being used to supply 2 separate 10A outputs, which I'm guessing is not the way it is meant to be used.

  6. #6
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    Quote Originally Posted by RJJ View Post
    Thanks GoldDigger for that explanation. I think i understand now. The way I see it wired in the enclosure in front of me is that it 2 10A inputs are being used to supply 2 separate 10A outputs, which I'm guessing is not the way it is meant to be used.
    When you say it is used to supply two separate 10A loads, that is no different from one 20A load. The two output terminals are internally connected directly together.
    Now if the two loads were variable and mainly combined to a total of less than 10A you will get redundancy. If not, then the module provides load balancing for whatever that may be worth, but if one supply fails, then the other will shut down from overload and the result will be that you lose both output loads, instead of just losing one as you would if the supplies were connected 1-1 to the loads.


    Sent from my XT1585 using Tapatalk

  7. #7
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    Quote Originally Posted by GoldDigger View Post
    It is, as shown in the block schematic, essentially a two diode OR circuit that combines the two inputs to drive the output without allowing one supply that fails to a low voltage to pull down the other supply.
    The two contacts, 13 and 14, provide an isolated (floating) dry contact closure that indicates that one of the two inputs is no longer working properly (output gone or voltage too low.)
    The only difference between this module and a simple two diode bridge is the monitoring circuit.

    You can combine two 10A inputs to provide 20A output, but falling back to 10A when one module fails or you can use it to combine two 10A inputs to one 10A output which will still be present after one of the two supplies fails.
    Quote Originally Posted by GoldDigger View Post
    When you say it is used to supply two separate 10A loads, that is no different from one 20A load. The two output terminals are internally connected directly together.
    Now if the two loads were variable and mainly combined to a total of less than 10A you will get redundancy. If not, then the module provides load balancing for whatever that may be worth, but if one supply fails, then the other will shut down from overload and the result will be that you lose both output loads, instead of just losing one as you would if the supplies were connected 1-1 to the loads.


    Sent from my XT1585 using Tapatalk
    Thanks again GoldDigger. I see the point you are making. From what I can see, the output terminals of this module (i.e. the two '+' terminals) exit this particular enclosure and provide power to two parallel circuits in another enclosure and the return line comes back and is grounded in this enclosure (with the module). I will have to use a clamp meter to figure out the amps drawn on these two parallel circuits. I doubt they add up to 10A, I expect the current draw on one to be in the order of about 5A and the other to be about 15A, but will have to see. It seems to be working at the moment though. I'm really not sure why this module is being used in this application in this way, I think whoever designed this should have just gone with a dual output power supply as opposed to one of these with the outputs internally connected.

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