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Van de Graff

  1. Oct 14, 2006 #1
    I built a VDG a few days ago and I was kind of saddened by it's lack of power. anything I can do to make it better?

    i was thinking to use a static control brush for the lower comb, and I might try a sphere of copper for the receptacle

    i don't know if my goal is viable, ut I want it to be able to raise my ~2in. hair
    and maybe a few other experiments like the classic bbubble experiment

    it creates about a .25-.5 in. spark at longest, and I dont know where I can get a better belt (I am currently using 'natural' spandex), how thick and what material should it be???

    any suggestions?
     
  2. jcsd
  3. Oct 14, 2006 #2

    Danger

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    If my experience is any indication, you should toss a couple of cats in there. I've gotten 3" sparks off of Lucy. :eek:
     
  4. Oct 14, 2006 #3
    haha, but i don't have any cats :(
     
  5. Oct 14, 2006 #4

    Danger

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    Hmm... that do present a problem. Seriously, I would suggest doing what I was going to do on your behalf and link you to. Use your Google to find what sort of static-production characteristics various materials have, particularly in regard to interactions between them. I'm going to go ahead and look into it myself, but you'll probably beat me to the answers. My first Google request will be: static electricity production materials
     
  6. Oct 14, 2006 #5

    Danger

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    Okay, here's something.
    http://www.simco.nl/info/about-simco/about-static/

    It would appear from this, if I'm interpreting it correctly, that the best combination of substances for your machine would be a Teflon belt with an asbestos comb, followed by a silicone belt/glass comb set.
     
  7. Oct 14, 2006 #6
    I thought that the combs only had to be conductive, with the rollers opposite in the Triboelectric series, with the belt neutral...plus, is asbestos even conducive?
     
  8. Oct 14, 2006 #7

    Danger

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    Sorry... a slip of the keyboard there. I didn't mean the comb; I meant the pad or block or whatever you are rubbing your belt on to cause the static build-up. The comb should be metallic.
     
  9. Oct 14, 2006 #8
    ok, so i have a nylon top roller and a silicone rubber bottom rollser with a spandex belt, i want to replace the belt... what can I use?
     
  10. Oct 17, 2006 #9

    Danger

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    What the hell does this mean?

    It popped up just now when I tried to use my own link. :grumpy:

    Anyhow, I might have the wrong idea about how your generator works. The ones that I've seen had some sort of rubbing block that the belt scraped as it was turning, and the comb pulled the charge off of the belt and into the ball. The composition of the rollers wasn't an issue. With a Spandex belt, it would appear that your rubbing block should be asbestos or glass. Maybe someone else should get involved here, because I'm not sure that we're talking about the same kind of machine.
     
  11. Oct 19, 2006 #10
    i wouldn't use asbestos -- rubbing it could be bad.

    http://amasci.com/emotor/vdg.html

    Be careful about the size you build. If you are not careful with a machine like this, you can get hurt/burned/etc.
     
  12. Oct 19, 2006 #11

    Danger

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    Good point about the asbestos, wx. And that's a great link. The machine there seems to be just like Ex-Storm's, and is indeed different than the one that I saw years ago.
    In this case, I'd keep the silicone roller and replace the other one with glass. I don't know how easy it would be to get ahold of a glass rod big enough, but maybe a nice smooth wine bottle with the ends cut off could work.
     
  13. Oct 20, 2006 #12
    whoa, glass? thats hard to handle
     
  14. Oct 20, 2006 #13
    well easiest way is to check for better materials for rubbing, and maybe getting a faster motor, or just load more current on the current motor...

    by the way, this site linked up there, is awesome, heh, i made a pendulum go crazy with an idea from that site, by using the electric field on a crt screen...
     
  15. Oct 20, 2006 #14

    Danger

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    Not if you have a glass cylinder and use it as a sleeve over a wooden dowel with an axle.
     
  16. Oct 20, 2006 #15

    moo

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    Wonder how hard it'd be to make one out of a treadmill...

    moo
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  17. Oct 21, 2006 #16

    Danger

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    It's not really a matter of how hard it would be, so much as how can you get enough hamsters running in the same direction... :uhh:
     
  18. Oct 21, 2006 #17
    you just need to find a fuse, and wear off the two metal caps from both sides, and there you have a glass cylinder.
     
    Last edited: Oct 21, 2006
  19. Oct 21, 2006 #18

    Danger

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    Isn't there a scaling problem there?
     
  20. Oct 21, 2006 #19
    Simple idea

    Sounds a bit simplistic, but I was on the Van de Graff for my school's open evening and it got so much better through the night as we put a powerful lamp right next 2 the belt to make it bone dry. But u've probably already thought of that.

    A cool thing 2 do with it once its working btw, is 2 light a bunsen burner with ur finger, making sure u earth the bunsen and insulate urself. Also piling tin foil cups on top so they fly away.
     
  21. Oct 21, 2006 #20

    moo

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    Lol, I figure a cat tied to one end should do it... :biggrin:

    moo
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