Re: Turn Spacing

To: tesla-at-pupman-dot-com
Subject: Re: Turn Spacing
From: "Barton B. Anderson" <mopar-at-uswest-dot-net> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Thu, 24 Dec 1998 08:52:29 -0700
Approved: twf-at-verinet-dot-com

Adam
Sounds like you found a sonotube form for your secondary. This is exactly what
I used for my 2nd coil and it has worked just fine as a form. Of course, it's
only as good as the initial preparation (sealing, etc..). I used 18 awg magnet
wire, close wound. I ended up at only ~32" winding height. In retrospect, I
wish I had wound the entire 48". I ended up trimming it down to the winding
length. For this size coil, it is a good idea to "not" go lower than a 4:1
height/diam. ratio. Big coils = big juice = big sparks (hopefully), and with
big sparks so close to the primary winding, the toroid to primary distance
becomes a factor best designed in than discovered later as an error. I plan to
add another 12" of winding to my secondary soon to correct my error. I don't
think 700 or 750 turns is going to play a huge role in performance, but
decreasing c-self via inner-turn spacing might be an advantage. Since I
haven't
wound anything except close wound coils, I'll let others comment who have.
However, I did want to point out some of my errors with this coil size as food
for thought.

One last comment. I would suggest mounting disks at each end (minimum) with a
2" pvc pipe mounted in the in the center and to the disks extending through
the
full length of the secondary for additional support. If extend up a few inches
above the top disk, it will also aid as a toroid support beam.

Big coils - Big toroids - Big power = BIG SPARKS!
Bart (still trying to get there)

Tesla List wrote:

> Original Poster: "Adam Parker" <park_e_r-at-hiwaay-dot-net>
>
> I just found a coil form that is 12.5"x48". I would like to own a coil will
> take higher powers (10kW+), but I'm not sure how I should wind this coil to
> prep it for high power. If I use no. 14 wire over its 46" winding length,
> closewound, I'll have 718 turns. If I use no. 16 wire spaced at 10 mils,
> I'll have 756 turns. I really don't know if larger wire or spacing is more
> important for high power survivability. Is 10 mil spacing too much? too
> little?  Thanks,
>
>                 Adam
>
> p.s. I've been getting my first "acceptable" output from my 6inch coil.
> only 15inches of spark. That'll soon change my better primary C!