Flyback Transformer Advise

Discussion in 'The Projects Forum' started by Obi_Kwiet, Apr 4, 2011.

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  1. Obi_Kwiet

    Thread Starter New Member

    Apr 4, 2011
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    My team and I are in the process of building a plasma speaker for a EE capstone project. We've already built a circuit and gotten the thing working, and we are currently in the refinement stage. Our first goal is to get it off of lab power supplies and use rectified mains, but I am also interested in finding a good standardized Flyback to use that will deliver consistent performance without a lot of guesswork. The reason for this is that we are all interested in taking an example home, some of us even want stereo pairs.

    After looking around the internet for a long time, I was only able to find a single Flyback with published specs. It's definitely on the pricy side, but if it delivers good performance and we have enough people interested to get the first price break, it will probably be worth it. I've already purchased one, and I'm going to test it out with a bench supply tomorrow, and hopefully we can retire our CRT flyback.

    This is a link to it: http://www.amazing1.com/transformers.htm
    The one I have right now is the FLYPVM500.

    Getting to the point this flyback seems to be built for this application, and is really quite a nice device, but I'm wondering what sorts of issues I might run into given the differences between it and a fly-back pulled out of a CRT. I don't know of any, but then I don't know a whole lot about transformers in general. Right now we're just switching a FET in series with the transformer, and the secondary has no connection to ground.

    I'd like to know more about the design and construction of Fly-back transformers, but that sort of info is hard to come by.

    Thanks!
     
  2. magnet18

    Senior Member

    Dec 22, 2010
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    Flybacks and HV devices are currently under discussion due to the dangers involved, and rectified mains is a definite nono here, so this will probably be locked shortly, but it's up to the mods.
    4HV.org might be able to help more, and general information on the operation of flybacks can be found here
    http://dos4ever.com/flyback/flyback.html

    I also had some flyback posts going on when I recently built a plasma speaker and used it for a science fair project
    (I varied the ultrasonic frequency and ended up finding out where the transformer went into saturation by measuring the maximum distance at which it could arc)
    namely
    http://forum.allaboutcircuits.com/showthread.php?t=51915
    http://forum.allaboutcircuits.com/showthread.php?t=50104
    http://forum.allaboutcircuits.com/showthread.php?t=49467
    http://forum.allaboutcircuits.com/showthread.php?t=50164

    and a video :D
    http://www.youtube.com/watch?v=vCI5RozQdTY


    Unless pinpoint precision is needed, theres no reason CRT flybacks wouldn't work fine, just about any will sound the same as another, especially considering the cost of a standalone flyback. Beyond that we'll have to wait for a mod's decision as to the existence of this thread.

    [EDIT]
    another great source of information on the operation of flybacks
    http://focus.ti.com/lit/ml/slup127/slup127.pdf
     
    Last edited: Apr 4, 2011
  3. Obi_Kwiet

    Thread Starter New Member

    Apr 4, 2011
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    Thanks for those links, that's very helpful information! I have no questions about the rectifier circuit, I only mention that we will be doing that. We will of course be following the policy of "flip the switch far away" :p

    We actually are using a CRT flyback right now, and it's working pretty well. The only reason we should change is to get a higher resonant frequency, and find a source of reliably similar flybacks. Another option would be to buy a bunch of different CRT flybacks and figure out which model works best, but that would be even more expensive, as many of them would be entirely insufficient.

    I'm thinking it would be a good project to open source and or sell as a kit, but that last option seems like kind of a long shot due to legal and safety issues.

    Since you have built one of these things before, did you have an issue with the HV return electrode heating up a lot? I know of no electrical or physical reason why this should be the case, but we've actually had the tip of a tungsten carbide drill bit turn red, and the other side remains cool.

    Here is a video of what we have if you are interested: http://www.youtube.com/watch?v=8YhdYLjaUlE
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    That is too bad, as the project becomes one we cannot discuss.
     
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