Re: Primary windings

["Garth van Sittert" <garth-at-mediasupplies.co.za> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Well done on starting your coil.

I too am pretty novice to coiling as well and have a low budget.  What size
secondary are you planning to use?  I used a 4,4" PVC secondary and the
copper didn't cost that much; R30 about $3 here in South Africa.

Your primary tubing is similar to mine.  It is not too small.  In fact I
wouldn't go smaller.  Due to the high frequency (+- 300kHz) currents in the
tubing during operation most of the current will flow on the surface of the
copper.  You want as much surface area as possible because of this 'skin
effect'.  The larger the better.  Your copper is fine for this power level
though.

I don't know if you should worry about the inverse conical shape for your
primary, I haven't seen too many people say that it is much better.  I heard
of someone getting 42" streamers from his 15kV 30mA coil and he used a
pancake primary.

Good luck!

Garth


----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, August 09, 2000 8:00 PM
Subject: Re: Primary windings


> Original poster: "Kelly & Phillipa Williams" <kellyw-at-ihug.co.nz>
>
> Hi experienced ones,
>
> (I am in the process of building a TC.) I have two 15 kV 30mA NST's as a
> power source
> and I am wondering if I can use copper tubing of OD 3/16 ths of an inch
for
> the primary coil
> in the from of an inverse conical spiral. Is this too large?
>
> Also, what is a good cheap source for secondary coil windings? I have both
> the primary
> and secondary windings from microwave oven transformers available as a
> possible source,
> are either of these suitable?
>
> Thanks heaps,
>
> Alan Williams. (kellyw-at-ihug.co.nz)
>
>
>
>