Re: A few questions about coil designing

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

Original poster: "Dave Leddon" <dave-at-leddon-dot-com> 

Hi Dave,

>BTW, what sized toroid and secondary coil length were you using
>to get 14 ft. arcs? That's about the spark size that I'm hoping
>to achieve with my finished coil.
The secondary was a 12.5" diameter pvc drain pipe and was wound 48" long 
with #20 heavy-build, about 1200 turns.  I ended up using two spun metal 
toroids, 32 x 8 and 26 x 6 inches spaced 9" apart with a 6" diameter 
aluminum cylinder (see picture):

<http://nick_tesla.home-dot-comcast-dot-net/Segmented_Gap.jpg>http://nick_tesla.home-dot-comcast-dot-net/Segmented_Gap.jpg

That strange looking contraption attached to the top toroid is a segmented 
gap, an idea I got from Dr. Resonance, that I use as a tuning aid.  Each of 
the movable sticks hanging from weed-trimmer line have a small nail through 
the bottom which direct the path of the arc.  The nail furthest from the 
coil is grounded and, in this shot, is at a distance slightly greater than 
14 feet.  You might be able to do better than this with a larger toroid and 
a 15 KVA pig driving 200 nf of tank cap, as suggested by Dr. R.  Just be 
sure that your arsg is up to the task.

Dave Leddon
Pleasanton, CA