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Any Tesla Coil fans out there?

Discussion in 'General Electronics Chat' started by DerStrom8, Feb 16, 2011.

  1. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    I was actually only thinking of buying one and compensating for the loss of capacitance by tapping the primary in a different spot. And I think that $24 is a reasonable price to pay if the capacitor would definitely work with my tesla coil.
     
  2. killivolt

    killivolt Well-Known Member

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    Remember you can make an offer. Give them $36.00 and take all of them.

    Tap the primary with one cap and test it for a proof of concept. If it passes your expectations. Attempt a parallel using the full coil.

    You can have 2 for backup or a second coil.
     
  3. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    That is a good point. I might do that, but I want to be sure that these capacitors will actually work for a Tesla coil in the first place. Is there anyone that can give me a definite answer for this?
    I greatly appreciate everyone's patience!
     
  4. dave

    Dave New Member

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  5. killivolt

    killivolt Well-Known Member

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    ReloadRon, is currently in the Chat Forum; looking at Designed for the Dump. Everybody else is offline. Maybe they will drop in sometime this weekend I'm sure they are following this Thread. It would be nice to hear from a few other member with experience on this subject.
     
  6. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    These are the two styles I have used and had great results from. They are most often referred to as 'Doorknob capacitors'. MuRata 40KV 920pF Ceramic Door Knob HV Capacitor TDK - eBay (item 310294476532 end time Mar-09-11 22:03:21 PST)

    and
    2200pF 30kV HV Doorknob Capacitors K15-4 Lot of 2 - eBay (item 190501866572 end time Mar-15-11 15:47:58 PDT)


    They are non polar and have very low ESR values which is great for spark discharge type circuits. I also recommend going at least 2x over your NST's rated peak output voltage being if your primary circuits are not set up right they can get subjected to a load of HV spikes well past the NST's output voltage.

    I would also highly recommend putting a fairly large ferrite core choke on your NST's outputs to greatly reduce the chance of internal flash over and permanent damage from any HF feedback as well.
     
  7. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    I've come across several Tesla coils (online) that use these, but I have somewhat shied away from them, myself, because of the price. I may eventually just break down and buy some, though, if I can't find a cheaper solution.

    This is in the plans. I have been wondering if you could use one of the coils of an MOT on each output of the NST to act as a choke, or if I should try something else. I ask because I already have a whole bunch of MOTs stashed away in the corner of my workshop somewhere. Would this work?
     
    Last edited: Feb 19, 2011
  8. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    Price wise you get what you pay for and there is a reason the good well constructed spark gap Tesla coils use them.

    I don't see why the secondary coils from your MOT would not work. I made mine from about 100 turns of 20 ga wire on old ferrite rods if I remember correctly. That didn't seem bother the HV at the AC line frequency but it did block the HF from going the wrong way.

    I have also found torrid cores work good too being they just hang out in the open there is no need for any HV insulation or anything on them.

    I would be curious to here what others have used to build them though. There seems to be many different ways of doing things other than how I built mine.
     
  9. BrownOut

    BrownOut Banned

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  10. killivolt

    killivolt Well-Known Member

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    I think he is looking for Bi-polar for AC. If they were testing it with DC would it mean it's Bi-polar?

    Good find though. Did you see the FREE Shipping and make a Bid Hmmm.
     
    Last edited: Feb 19, 2011
  11. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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  12. BrownOut

    BrownOut Banned

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    It's a polypropylene cap, which would make it ideal for a TC.
     
    Last edited: Feb 20, 2011
  13. BrownOut

    BrownOut Banned

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    I don't see any reason why this wouldn't work. If you are concerned, you might try finding a TC forum and see if anyone uses these kind of caps. Otherwise, see if you can find a manufacture's datasheet. Thing to look at will be lifetime derating for frequency, surge current, etc.
     
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  14. killivolt

    killivolt Well-Known Member

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    He's probably spent money and been burned by the lack of supporting information like me. I still have 2 Flybacks mounted on some old zenith boards I paid $60 a piece, thinking they would work with what I'm doing. So, now I think I'm going to feed them an input to the H.O.T from a good regulated power source and tap the output spark gap it to Neutral.

    I don't need a TC, just a small spark gap will do.
     
  15. BrownOut

    BrownOut Banned

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    I just use old ignition coils. They never fail to work.

    OH, and take it from me; do not use a regulated power supply for your HV experiments.
     
    Last edited: Feb 20, 2011
  16. killivolt

    killivolt Well-Known Member

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    Ok, I thought that's all a Television uses. It there some sort of comparator reference an LLC or something?
     
  17. BrownOut

    BrownOut Banned

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    I meant "automotive" ignition coil, the thing that makes your spark pulgs spark.
     
  18. killivolt

    killivolt Well-Known Member

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    Yes, I'm very :ahem: experienced with it. Especially when you try to get a spark plug on your lawnmower to spark to see if the Magneto is generating and your not properly ground the plug.

    O, that bites

    Edit: Oh, and yes I have been bit by a coil too!
     
    Last edited: Feb 20, 2011
  19. BrownOut

    BrownOut Banned

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    Don't mean to be condenscending. I never know what someone's automotive experience is.
     
    Last edited: Feb 20, 2011
  20. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Thanks, BrownOut. This is very helpful :) I just joined 4HV, so I hope to be able to get some help, there.
    Many thanks!
    Der Strom
     
  21. killivolt

    killivolt Well-Known Member

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    None taken. I was talking TV and you were talking Automobiles. Tomato - Tomahto.

    I grew up around reciprocating machines. Be they combustibles or compression. Not much experience with rotatory, except with refrigeration compressors.

    At 13yrs old I was replacing brakes and doing small repair in my Uncles Automotive Repair Shop. The first motor I tore apart was a 5hp Briggs and Stratton. I was 9yrs old and I used cheater bars because I wasn't strong enough to loosen the bolts :p

    Edit: I gotta get going. Thanks for all your input I'm learning a lot.
     
    Last edited: Feb 20, 2011

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