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High voltage power supply chassis

Discussion in 'Electronic Design' started by [email protected], Sep 13, 2007.

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  1. Guest


    I've just started an Associates level Biomedical Engineering
    Technology program and we have to design a power this semester in
    Multisim for my Electronics class and I also have to design on paper
    an X-Ray machine for my Rad Physics course. I would like to actually
    build a power supply that can produce volts that range from 1000 V to
    60000 V. For starters, what type of chassis should I use?

  2. Red.

    Best regards,
    Spehro Pefhany
  3. John Larkin

    John Larkin Guest

    Metal, probably. Big.

  4. Yukio YANO

    Yukio YANO Guest

    Color TV Chassis !

    Add a Second Voltage Doubler for 30-60 KV !

    TV's are limited to ~ 25 KV to prevent Higher Energy X-Ray generation !

    Using a TV High Voltage stage makes lots of sense, and the current range
    is about right too !

    You would have to solve a 30 KV capacitor problem, maybe use an old
    Picture Tube ?

    You wouldn't have to obtain a high Voltage Transformer.

    Crockroft-Walton ? circuit comes to mind.
    Yukio Yano
  5. This is totally off topic, but Yukio are you Japanese? ???????????????

  6. Rich Grise

    Rich Grise Guest


    Good Luck!
  7. Hal Murray

    Hal Murray Guest

    Bakelite is actually not a good choise. The problem is that
    it "tracks". If you get some leakage across the surface (say
    because it's dirty) the surface turns to carbon. That carbon
    conducts slightly which draws more current which makes more carbon...
    It spirals downhill fast.

    I'd use a metal chassis with ceramic standoffs.

  8. Well for one thing, a 15kV supply can fit six in a pack of cigarettes
    for a mere 20uA requisite.

    For mA levels or more even, one needs a bit more kick in your

    You would not want a supply that can be adjusted over such a large
    range either.

    You want one that makes 1000V at up to a few mA to a few tens of mA.

    For the X-ray supply, it depends on the tube size. I have seen
    everything from gas pipe X-ray supplies that are a mere 4kV at 1mA and
    0.000006% ripple, and I have seen 50kV @ 200mA for a supply we made for
    LANL to peer into nuke casings.

    You need to define your power requisites, then you can have a clue as
    to how big your output transformer that pumps your multiplier stage needs
    to be, etc.

    A supply that runs the gamut from 1kV to 60kV and a mA or so to the
    needs a 60kV driven X-ray tube would need is just not very feasible.

  9. To get a 60kV X-ray supply from TV anode supplies, take two. One at
    +30kV, and one at -30kV. X-ray tube gets driven at 60kV, and the
    radiation of the supplies remains low.
  10. whit3rd

    whit3rd Guest

    If you're gonna be changing the supply, you'll start with a small tank
    insulating oil (like, 50 gallons of Diala AX or somesuch). Air is
    insulation at 10 kV and above, so one either uses potting compound
    like a TV supply, or a vat of oil. Potting the circuit would make it
    hard to change, so... oil.

    As to the rest, 1000 to 60,000 is a wide range; without knowing the
    current requirement, it might be a little motor-driven Van de Graaf or
    a switchmode power supply with Cockroft-Walton rectifiers.
  11. 50 gallons of specialized transformer oil will be costly.

    Cheaper, and much more serviceable to get a gallon of fluorinert:

    It will allow one to place un-potted supply stages under power safely,
    and without the oily mess.

    1500 V per mil dielectric strength.
  12. Andrew

    Andrew Guest

    This is definitely not a beginners project. 60kV will arc over enough
    distance to kill very easily. Real products that I have worked on use
    either teflon, vacuum, or about 1 foot of air as the insulator. Also
    much mechanical construction with just the right materials. So that when
    they do fail, which does happen occassionaly like when the output gets
    shorted, an arc doesn't jump through the controls and take you out with
    it. Your best bet would be to go and take a look inside some
    pre-existing boxes and get some service manuals and have a good long
    read. You will need more than 5 minutes on Google to get a safe result.

    regards Andrew

  13. RIGHT. How do you propose that two be cascaded, dim bulb?

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida

  14. They don't get cascaded, dumb ****.

    They are both full floaters, and you tie the negative lead of one to
    the positive lead of the other and ground that node. Then, you have a
    plus 30kV supply and a minus 30kV supply wrt ground. The x-ray tube is a
    full floater, so the +30kV and the -30kV fed into it yields 60kV at the

    The last X-ray supply I made was two 90kV supplies set up in this exact
    manner, and it fed a Palladium target (about 20 grams) $900 X-ray tube at
    180kV. It was all set into a steel cased lead lined box with oil, and an
    expansion tank, and the whole thing weighed over 150Lbs, and that was
    without the front end driver/control supply. It was not a flyback method
    driver either. I've got pictures here somewhere I can post in abse.

    That is the supply/X-ray source that is under the conveyor at your
    local airport, looking at your carry on luggage.

    So **** you.

  15. You don't know anything about second anode supplies then. They are
    cast in epoxy, and not designed to float.

    The only 'floater' was the defective condom your dad used. You are
    as ignorant of TV power supplies as you are about most things, dim bulb.

    You just admitted that you're shooting blanks, as usual.

    No thanks. I prefer a woman, and human. BTW, congratulations on
    having a new strain of VD named after you.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
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