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Thread: Experimentonomen´s first argon.

  1. #21
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    I have now designed a preheat timer with interlock to make the laser idiot proof, ie to prevent turning it on while the tube is cold, the preheat time is about a minute.

    Schematic:

  2. #22
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
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    One of the zeners in series with 100 or 200 ohms will cover you.

    And for the blocking diode i plan to use one or two of these instead of that 1N1190 because i have two i front of me as i type this and i also have the proper heatsinks they screw into:
    http://pdf1.alldatasheet.com/datashe.../SKN20/12.html[/QUOTE]


    Yep, fine, its the big die in the diode that protects you, not the overvoltage rating, so the semikron part is just fine.

    The HV return cap is usually a .1 uf to 1 uf metal can mica sprague or a plastic film 600V WIMA HV film cap. you can see its placement in the lexel 88 head schematic in the FAQ.

    sorry, took me a while to get back to you, was in hospital.
    Qui habet Christos, habet Vitam!
    I should have rented the space under my name for advertising.
    When I still could have...

  3. #23
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    Sounds good, thank you!

    Now i just need to hunt down a 10000µF 200V capacitor to keep the voltage smooth.

  4. #24
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    Unhappy

    so i´ve gotten some work done on what is eventually to become a psu, you´ll have to excuse the mess.

    Some pics:













    Now to the bad news, during a test earlier today i had the voltage at about 140VDC using a 230V 800W heater in parallel with a 230V 2000W heater to simulate a laser tube, i was successfully able to turn the current down from 7A to 3.6A, but only for about 2 seconds before the current shot back up to 7A and the pot no longer did anything, despite having the current spread out over 6 mosfets, atleast one still failed within seconds. The heatsink never made it past luke warm.

    Its looking more and more unlikely that i will ever be able to build a working psu and more and more likely that im gonna scrap all this and just buy a fucking psu on ebay.

  5. #25
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    That's the spirit!


  6. #26
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    don't give up

    I did the same fidling building a variable flyback PSU with the same mosfets... had some popped, had some smoke, but finally achieved the goals

    that was a H bridge PWM driven flyback transformer from a sony trinitron computer screen, powered from a bipolar 50VDC 5A source (those transformers are heavy, and they work VERY well for such things as powering a TEA or a small tesla coil)

  7. #27
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    I´ve started on a new passbank using eight 2N3716´s, if this doesent work, i´ll give up!

    Pics:



  8. #28
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    wow, that's a big one!

    did you try to drive your mosfets with a PWM signal? since they are designed for switching applications, they might work well

  9. #29

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    Quote Originally Posted by Experimentonomen View Post
    if this doesent work, i´ll give up
    No, no, no !!!

    Quote Originally Posted by Experimentonomen View Post
    Do I see it right that all white resistors shorted by green wires ... ?

    Do you have a schematic of all the electronics there?

    Have you seen this thread on 4HV: http://4hv.org/e107_plugins/forum/fo...php?65917.post ? User kilovolt made a PSU like this.
    http://c4r0.byethost9.com/ - If you like lasers, high voltage, x-rays and stuff like that, check out my website

  10. #30
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    The green "wires" are 330ohm resistors

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