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24-30v dc power supply schematic

Discussion in 'Electronic Basics' started by chas, Oct 29, 2012.

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  1. chas

    chas Guest

    I need a schematic for a non regulated 24 or 20v dc power supply.
    I will be running high amps (15?) for a homebuilt induction furnace.
    .. . . in advance to one and all. . .thanks. .. chas.
  2. Rick

    Rick Guest

    For high current designs a full wave using a center tap transformer is more
    efficient, it makes better use of the iron in the transformer and you only
    have one diode drop.
  3. Jamie

    Jamie Guest

    Let me get this correct here, you'd be happy with a 24V AC or
    20v DC supply?

  4. chas

    chas Guest

    120 v AC imput and either 24 or 30 v DC output. Need higher output amps for
    the furnace.
  5. chas

    chas Guest

    I'm at a loss on how to view this.
  6. you're going to make an induction furnace, but need help with the brute
    force power supply?

    a plain bridge rectifier and some giant caps is probably fine for what you
    need. something around 20VAC from the transformer will be about right.
  7. P E Schoen

    P E Schoen Guest

    "chas" wrote in message
    Since you only need about 300 watts you might be able to use the 12 VDC from
    a couple of old computer power supplies, in series. A 400W supply usually
    has 12V at 15 amps or more. You may even be able to hack it to get what you
    need with one unit, and if you can use the frequency of the supply for the
    induction furnace, you may be able to tap off before the output rectifier
    and use it directly on your induction coil.
    (12V 14A, $10)
    (12V 22A, $16)

    You can also get single output switching power supplies for 15 amps or more: ($15)

  8. Jamie

    Jamie Guest

    actually, I was thinking he could gets his hands on a 24 volt charger
    from an auto parts store.

    I have a large garage charger I gutted out and made a heavy duty 13.8
    volt supply to test run 12 volt auto equipment.. I got large caps in
    there filling the hole and a soft start. N channel power mosfets sinking
    the (-) side output through an inductor to switch mode regulate it.

    Works a treat, the caps are in 2 stages, one set before the switch and
    another set after.

    I figure even if it fets shorted, the full output isn't that much
    higher, some equipment should handle it. ;)

  9. Les Cargill

    Les Cargill Guest

    That's what I'd always heard. You need center tap only if you
    need output balanced about zero. It's also easier to filter the
    output from the bridge with a solid ground reference.
  10. Jasen Betts

    Jasen Betts Guest

    that only wrks if you plug one of them into an isolating transformer.
  11. whit3rd

    whit3rd Guest

    An easy option is two car batteries in series, with a couple of
    chargers attached. If the induction furnace only operates for a
    few minutes at a time, you can switch the batteries from series to
    parallel and charge 'em offline.

    Anything DC has to be filtered, if not regulated, and 15A of ripple
    current is going to require some thought. Car batteries might
    be overkill, but as long as the problem gets dead...

    If you decide to get a regulated supply, there's surplus options. Consider:

  12. Phil Allison

    Phil Allison Guest

    ** That is 100% WRONG !!!!!!

    ** The link is full of damn silly errors, shame on Hammond.

    A full wave bridge plus filter cap is the most efficient by far.

    And to a close approximation, peak DC and average DC are the SAME !!

    .... Phil
  13. P E Schoen

    P E Schoen Guest

    "Michael A. Terrell" wrote in message
    The negative MAY be connected to the case, but certainly not to the power
    line neutral. So you may be able to remove the case ground connection, or
    just float the second supply case 12VDC above the other. Here is a schematic
    of a 300W ATX supply showing the separate grounds:

  14. P E Schoen

    P E Schoen Guest

    "P E Schoen" wrote in message
    Here is an article about using two server PSUs for 24 VDC:

    And here is a good article about using components from a PSU to build your
    own, with high efficiency synchronous rectifiers:

  15. that depends on the voltage you want from the power supply. If you want a
    low voltage high current supply, a bridge rectifier can be a poor choice.
    that's if there's no ripple. They never defined it, so yeah you could
    question the pdf.
  16. Phil Allison

    Phil Allison Guest

    "Cydrome Leader"

    ** Nonsense - a bridge rectifier always uses the transformer more

    ** ROTFL !!

    THREE completely undefined and unsupported claims, what rubbish !!!

    ** Try reading the whole sentence - piss head.

    What a posturing fuckwit.

    ..... Phil
  17. Phil Allison

    Phil Allison Guest

    "Jamie" = radio ham moron: Maynard A. Philbrook

    ** **** off and die

    - you stinking pile of AUTISTIC septic shit.
  18. Jamie

    Jamie Guest

    You're slipping again! It seems like it is becoming a habit lately.

    I won't go into the obvious reasons why, you seem to be inadequate
    lately to understand much, your responses show it.

    Perfect example of your dissolving brain cells.
    Get off the sauce, it's effecting your judgment.

    And I thought the drugs here in the states were better, maybe I was
    wrong about that one ? Actually, I was mistaken.

  19. Jamie

    Jamie Guest

    You just can't handle it when you slip up.. That's too bad too,
    I was hoping you'd stick your neck out even future, but you
    have chosen the usual imodium.

    Stick your nose in google some more, maybe you'll get it
    correct the next time..

  20. I want to hear more about how you'd make a 2.2 volt 100 amp linear power
    supply with a bridge rectifier, and what sort of single digit efficiency
    you'd expect to get from it.
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