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Competition: High Voltage Power Supply

Discussion in 'High Voltage' started by DerStrom8, Jan 18, 2013.

  1. tvtech

    tvtech Well-Known Member Most Helpful Member

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    This thread is beginning to look like an Agatha Christie novel... WTF is going on here?

    Anybody know the plot. Who dies first...the Designer, Inventor or a Random Forum Member :D

    Regards,
    tvtech
     
  2. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Hahaha, you're right :D Didn't realize how this all was starting to look. Hopefully you got my point though ;)
     
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  3. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Then my 12 KV 60 Ma neon sign transformers must have very conservative ratings being when I used them for Jacobs ladders I had to have the top of the ladder rods at least 8" apart to consistently break the arcs.

    I already made my idea submissions and got shot down.

    Post 14, Arcs Vs sparks issue.Nope. :rolleyes:

    Post 18, Over clocked and over driven driven 15 KV NST with inverter controled what nots. Nope. too heavy.:(

    Post 20, two variacs and NST. Too heavy. :(

    Post 33. Common flyback transformer with single transistor power oscillator. Nope. Now I am just picking. :confused:
    --------------------------------------------------

    So lets all of us get this strait on what it isn't.

    No NST's or the like. Out for being too heavy/bulky.

    Common CRT flybacks cant come close to the requested output power requirements but that's what the design should be built like.

    There is a criteria of it can be AC or DC but it has to make arcs not sparks.

    There is leeway on the design and output but not relating to what anyone has posted so far.

    It has to somewhat match the characteristics of a flyback transformer but the defined requirements are way beyond what any off the shelf flyback can deliver.

    The OP is open to anything but what has been suggested.

    It has to run for 24 hours continuous duty but has no defined/specified input power source criteria.

    What the contest sponsor wants cant be accurately defined but what he doesn't want can but only after its suggested.


    Clear as mud to me. :confused:

    I give up but I will be watching with morbid curiosity to see where this leads.;)
     
  4. dave

    Dave New Member

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  5. tvtech

    tvtech Well-Known Member Most Helpful Member

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    Hi tcm

    I will be watching only too.

    Gotta see how this unfolds :D

    tvtech
     
  6. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    I am not quite sure what you mean by that.

    Using either higher frequency or large (expensive) capacitors, you can meet the requirements for voltage and current with a neon sign transformer (or similar) plus a 2 stage multiplier. At 60hz, and a 10% voltage drop, you would need something like 1.2 uF capacitors (!).

    Now, of course, the transformer won't fit in the designed space. X-ray machines have been around a long time as has HV physics, and so far as I could find, that basic design , i.e., a transformer to get to ≈ 5000 to 6000V followed by a voltage multiplier, is still being used.

    You could up the frequency and reduce the capacitors proportionately, but you are still going to have some expensive components. Do you have that stuff on your shelf at home?

    John
     
  7. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Okay, I am only responding to this because I think it will help some of the members here who are actually interested in trying to make it work, rather than just picking on the competition.

    Correct.

    The original output power requirements were very rough since the host was not sure of the output specs that he really wanted. He has since specified that it simply has to operate like it would in its original TV application.

    The output of a flyback transformer is already DC. The host has since specified that that is what he would prefer.

    If you're referring to your suggestions, they were too far outside the preferred boundaries, namely in the weight and size category.

    You're repeating yourself now. Look at the third item in your list.

    Again. See the 5th item in your list.

    Correct. That is for the designer to decide.

    Most of the ideas that have been turned down directly go against what was already specified in the criteria. Anything else has been edited into the first post.

    Enjoy the show tcm.
     
  8. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Sorry, anytime I've used a doubler or tripler, it's turned an arc into a series of loud sparks, due to the output waveform and the energy stored in the capacitors each half cycle. I suppose there are ways around that, I've just never seen it. I should not have jumped to conclusions though.
     
  9. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    I am sure you have seen this calculator: http://www.extremeelectronics.co.uk/index.php?page=cwvoltage

    If you assume that there will be some sort of voltage multiplier, you can play with the numbers to test for reality.

    Here are some other sources you may have seen:
    http://www.electro-tech-online.com/custompdfs/2013/01/Multiplier20Design20Guideline.pdf
    http://www.voltagemultipliers.com/
    http://www.electro-tech-online.com/custompdfs/2013/01/anusingr.pdf

    However, if you are not limited by reality, then this Instructable presumably tells how to get a 0-50KV variable supply at 20 mA:

    http://www.instructables.com/id/High-Voltage-Multiplier/

    I couldn't find any experimental documentation of that claim in it, but that is the claim and how it is indexed.

    I am not trying to shoot down the next X-Prize in HV physics. I think this project is doable within the bounds of what is known, except for weight and size.

    John

    Edit: Are superconductors and exotic insulation materials ruled out?
     
    Last edited: Jan 21, 2013
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  10. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    The host has responded and has asked me to add these new specs. I will also add it to the first post:

    I realize things are changing up a lot, but that is because the project is not specific. The designers should make most of these decisions on their own.

    Regards,
    Matt
     
  11. tvtech

    tvtech Well-Known Member Most Helpful Member

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    Why can "the host"...not just "post" here?? Under an Alias ??.

    Instead of this "host" nonsense?. Middleman Matt. Who can not answer all the "hosts" questions ??

    Too tired for this game.

    tvtech
     
  12. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    I don't know why the Host has elected to remain separated from this thread, but he has every right to. We are still in direct contact so that he can answer any questions you have. He chose me as a middleman because I was trying to help him out privately with the project at first, before he decided to make it into a competition.
     
  13. tvtech

    tvtech Well-Known Member Most Helpful Member

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    Oh well, Sally says if I don't go to bed soon..I am toast. Don't want that.

    Enjoy the "Host". Whoever that mysterious person might be.

    As Charlie Harper often said......" I have a bad feeling about this".

    Regards,
    tvtech
     
  14. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    To be honest, I don't see what the problem is. He will probably reveal himself at the end.

    Now, is anyone actually interested in giving this a try? Or is everyone just going to complain that there's not enough information? It would be good to know what's happening ;)

    Regards,
    Matt
     
  15. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I would have thought chances are slim :p

    "Small reward given for creation of unknown project, applicants must wear a blindfold, have one hand tied behind their back, and the fingers of their other hand broken".
     
  16. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    It seems you are misunderstanding this just as much as other people are. This design is about ingenuity and overall design technique. The designs are merely a method to judge the contestants' ability to take a small amount of information and materials, and put it together in the cleverest way possible.

    The applicants are not blindfolded, nor do they have a hand tied behind their back or fingers broken. In fact, it's the absolute opposite. They're completely free to do whatever they want provided it produces an operational device.

    I honestly don't see why people are having problems with this. The guidelines are not very strict. It simply has to provide a ~20kv output, variable voltage and current, not weigh a whole lot or take up too much space, and be as cheap as possible. The rest is really up to you.
     
  17. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    In hopes that it might induce a little INTEREST in the competition, the host has upped the prize to $100 under one condition: Stop asking questions and put your mind and ingenuity to work! ;)

    If you use the given criteria to create a design, you will have a good chance of winning. It's that simple.
     
  18. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    So just to get an idea, who is interested in participating? Again, the grand prize has been increased to $100!
     
  19. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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  20. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    I will have to ask the Host, but I think it's fairly close. All that it's missing is an adjustable voltage and current output. Also not sure about the two transformers. I don't think it will be a problem, but again, I'll ask the host.

    Thanks for the input John :)
     
  21. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    The voltage is probably most easily controlled at the input, e.g., a variable transformer. As for current, most of the modern self-oscillating, half-bridge drivers I could find only operate at 50% duty cycle ±2%. Fairchild makes one that can be externally driven to give adjustable duty cycle, FAN7387 (http://www.electro-tech-online.com/custompdfs/2013/01/FAN7387.pdf).

    It is interesting that IR compares its drivers to an NE555, but they do not have separate charge and discharge paths. I wonder whether the same approach (i.e., external PWM drive) as used on the FAN7387 could be used with the IR driver to get variable duty cycle and current control. Anyway, how important is current control, if you can control voltage or vice versa?

    John
     
    Last edited: Jan 23, 2013

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