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First Tesla Coil hints?


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From:  Shaun [SMTP:shaunobrien-at-geocities-dot-com]
Sent:  Saturday, February 21, 1998 9:40 PM
To:  Tesla List
Subject:  Re: First Tesla Coil hints?

>From:  Scott Cutler [SMTP:spcutler-at-ucdavis.edu]
>Sent:  Saturday, February 21, 1998 7:34 AM
>To:  tesla-at-pupman-dot-com
>Subject:  First Tesla Coil hints?
>
>>>4" x 14" secondary, 24 gauge wire
>
>>Not by any means long enough.  Go for a 4"x20" at least, 22"
>>or so preferable.
>
>You're probably right, but I read in several places that I should keep the
>diameter to length ratio under 4:1.  Actually, though, the real reason
>it's not longer is because I ran out of wire.  BTW, sewing machines make
>great winding machines for small coils.
>
>>>Standard spark gap, 2 1" metal spheres (metal drawer knobs)
>
>>As you probably know, multiple gaps help ALOT, I can't emphasize
>>exactly HOW much they help.
>
>Interesting.  I'll put that on my "to-do" list.
>
>>>Bottle capacitors (read on)  6 turns 1/4" copper tube conical primary
>
>>Most of my coils have at least 15 turns on the primary, although if
>>you are going to use a 14" secondary, this would probably be ok.
>
>Yes, that's about what I figured.  My next coil will probably be about 36"
>and have about 15 primary turns.
>
>>I'm 18, and you? :-)
>19.  I go to the University of California, Davis, but you probably already
>figured that out.  I actually started this in high school, but have put it
>off until now for financial and time reasons.
>
>>I have personally found inclined to be the best as well.  I currently use
>a
>>15 degree primary for my 6", but 20 degrees is great too, better in fact
>>I would think.
>
>Cool.  I made the form by bending acrylic; boy, was that a mistake.
>Took hours and hours.  Next time I'll use something else.
>
>
>>As for the cap, don't worry.  I used the EXACT same plans when building
>>my first salt water capacitors.  They work well, although they will fail
>>eventually
>>like any other capacitor if you leave out the oil.  I ran my bottle caps
>>for about
>>20 minutes nonstop once and they kept going.
>
>Ok.  I found some 40 kv 2.7 uF doorknob capacitors for $16 each.  Two of
>these would do the trick.  Would these do well?  Is the price decent?
>
>>You want to put your capacitors in series with the primary, and have the
>>spark gap in parrallel with the transformer.  This is safest on your neon
>>transformers.  As you've probably heard, they aren't really made with
>>Tesla coil use in mind.
>
>Yes, that seems to be the consensus nowadays.
>
>>Well good luck!
>
>Thanks!
>

Scott,

    The cap value depends on the voltage and current of your transformer.
Use this to find the cap value for your transformer. First find the
impedence of the transformer. impedence = voltage/current. cap =  1/(2 x pi
x impedence x .00006). The .00006 is the 60Hz line freq in the U.S. If you
have one neon transformer lets say 12Kv 30ma then the right cap value would
be .0066 uF. Hope this helps you.

Shaun O'Brien