Re: beginner coil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "ka1bbg by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ka1bbg-at-webryders-dot-net>

Hi, well sounds like you have had a lotta fun building stuff. we all started
that way. good luck and may your sparks grow longer! cul brian f.


----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, December 17, 2001 1:19 PM
Subject: beginner coil


> Original poster: "Chris by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<chris-at-atomic-pc-dot-com>
>
> Hi everyone,
>
> Just for fun, I'd like to share the specs of our first working coil with
> the list...
>
> --Transformer: 10 KV, 20 (?) mA Oil burner trans.  My friend used to use
> it for a Jacob's ladder.
> --Capacitors: 7 Snapple bottles, foil on outside, salt water on inside
> --Spark gap:  2 large bolts PC-7'ed onto wood block (from my first
> attempt at a coil)
> --Primary:  Inverse conical of 8 turns of 3/8" copper refrigerator
> tubing, zip tied to 3 wooden stakes, looking sort of like a stove burner
> bent into a wok shape.
> --Secondary:  440 turns of #24 enameled magnet wire.  (This was the
> whole roll that we had, so that was our limit)  wrapped on a 3" (inside
> dia) PVC pipe, winding length 10 inches
> --Top load:  brass drawer pull knob from hardware store, but we made a
> toroid out of duct tubing and it makes the sparks shorter but brighter /
> louder... also more "sting" to them, even though I already know you're
> not supposed to touch it....
> Alternatively, we top the secondary with a clear light bulb for a plasma
> globe...
>
> The coil throws sparks about 4 inches long, maybe 4.5;  we've found it
> gets a little better when we put a ca. 6000 pF capacitor (homemade also,
> rolled from PVC shower pan liner)  in *series* with the Snapple cap
> bank... although we don't know the exact capacitance of the bank, I'd
> estimate it to total around 5500 to 6000 pF (sound right for 7
> bottles?)... I guess the series connection makes sense because the res.
> freq. is so high for such a short secondary (less capacitance required)?
>
> I know from reading the list and the web that this spark length isn't
> amazing, but at least it's a start...  I just have to sit down and do
> some actual math now...  for a pic of the coil's secondary and some
> other junk, go to http://www.atomic-pc-dot-com/workbench1a.jpg
> (see if you can pick out the "glue stick micro coil"... which threw a
> decent spark for about 10 seconds before it arced through the hi-tech
> bond-paper / scotch tape primary "insulator")
>
> Best regards,
> Chris
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