Homemade High Current Power Supply

Discussion in 'Homebrew and Kit Projects' started by KD8RYP, Apr 30, 2012.

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  1. KD8RYP

    KD8RYP Ham Member

    Thought this might be interesting to some people. I've been building a high current variable DC power supply from scratch, and recently just got finished with it. It's variable from 8vDC - 24vDC and I've loaded it down with 20A and the transistor's, regulator, and transformer isn't even touched. It's made with (6) 4800uF powerlytic caps for the filtering, and (8) power transistors along with a .1ohm 25watt resistor to balance the current flow in each resistor. There are (2) meters that read voltage and current draw. The massive heat sink was taken off of a old car audio amplifier that no longer worked. There is a relay that closes when the ON/OFF switch is flipped that applies power to the transformer. Their is also a cooling fan that blows air up through the case and across all the transistor's. There are pictures in the uploaded attachments.

    Thanks! 73's KD8RYP - Andrew
     

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  2. AF6LJ

    AF6LJ Ham Member

    That is nice.
    What regulator chip did you use?
     
  3. KD8RYP

    KD8RYP Ham Member

    Thanks. It's a LM723 voltage reg chip. It's on a small PCB board from radio shack that sets in the controller box unit. I used a Amphenol connector to connect the controller box unit to the transformer enclosure unit.
     
  4. AF6LJ

    AF6LJ Ham Member

    Very cool......

    About the time I was completing building a power supply to give my OEM supply a rest someone handed me a 63A switcher. I may do it anyway, I have all the parts.
     
  5. KD8RYP

    KD8RYP Ham Member

    It's very heavy and a pain to move around but its worth it getting experience in electronic projects. I checked the DC out signal on a scope and it has hardly any ripple even when loading down to 20A.
     
  6. WA7PRC

    WA7PRC Ham Member

    Sounds similar to the "RF Proof 30A Power Supply" I built some years back, based on a 723. Only the outer cabinet and heatsink was off the shelf. I homebrewed everything else, including the PCB, chassis, and rewinding of the transformer. It runs out of steam at about 27A.
     
  7. KD8RYP

    KD8RYP Ham Member

    I haven't got the chance to load it down, but my guess it'll handle 35-40 Amp load continuous and surges of up to 50 Amps.
     
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