What drives the 30A limit per bank on the P12R?

Discussion in 'EthConGateway by Joshua 1 Systems' started by nutz4lights, Jan 26, 2013.

  1. nutz4lights

    nutz4lights Full Time Elf

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    Hey all,

    Is it the 3oz copper on the power distribution board that drives the 30A limit? Each output can handle up to 7.5A by the fuses and there are six outputs, so you would think that, if possible, they would set the fuse per bank to 45A.

    The reason I'm asking is that I want to use a P12R to control 24 x 50 count strings (two per output) that are 5V. Each 50 count string will draw 15W which is 3A @ 5V. Two of those on one output is 6A, which is fine by the per output fuse limit, but six of those on one bank will draw 6 x 6A = 36A which would blow the fuse on the bank.

    I know I can power inject per Option 3 in the ACL P12R guide, but it would be so much easier to just run the power off the bank, so I thought I would ask what is driving the 30A limit.

    Thanks,

    -Louie in Melbourne <Florida>
     
  2. j1sys

    j1sys There are no rules, and those are the rules. Community Project Designer

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    it IS the copper. there are also some maximum ratings on the fuseholder that the 30amp is installed in. So we limited it to 30A with the Fuse. Even so, we don't recommend continuous 30A loads.

    it is theoretically possible to scrape away the coating on the copper traces and solder some braid or heavier wire to add to the mains ampacity but we don't recommend it.

    -Ed
     
  3. OP
    OP
    nutz4lights

    nutz4lights Full Time Elf

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    Thanks for the reply. I figured that was the case. I do some PWB fab here at work, so when you take the time to specifically mention that there's 3 oz copper on the power distribution board, I understand you're going out of your way to make it as power capable as you can. I try to limit most of our engineers to 1/2 to 1 oz copper, but that is because they're asking for routing traces that are 40-50 micron in size... ::)

    Looks like I will end up driving 1/2 the strings through the card (18A per bank) and the other 1/2 off the power supply.

    Thanks!

    -Louie in Melbourne <Florida>
     

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