Re: flat coil ?

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

Original poster: "Chris Swinson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <exxos-at-cps-games.co.uk>

Hi Bart,
>
> Actually, the other direction will gain a high Cself (400" height  and 3"
> dia. [high hd]).


I tried 200" H, 10" dia, this gave 60.25pf. 6.27mH
I also tried, 10" H, 200" dia this gave 519pf , 12.8mH

Wintesla wouldn't work well with 400" I think it jumps to nf becasue it
comes out as 0.010.


>
> >  Its interesting that there can be so many possible
> > combinations for L and  C  with the same length of wire. I wish I could
try
> > such a high Cself coil, Would probably have to use the outside of the
house
> > for a form that large though :)
>
> If you think about cap construction (number of plates, surface area,
> insulation thickness), all that
> changes with these different geometry's which is why you get such a high
> Cself. It would be fun to do
> it just for giggles, but it's just physically impractical. Something else
> which you might find
> interesting is how low Fres goes. Part of the "impracticality" is the
> primary circuit. You would end up
> requiring a tank cap around 1000uF for dual-tuned resonance. Can you
> imagine what it would take to
> charge such an enormous hv cap.
>

Thats true, I think one of those coils was 61khz.  I've known coils run on
48khz before now though so I guess its no too bad...  Though I did build
some 2.5" dia 90" high coils but never tried them, I think it was with 0.4mm
wire.  I am not sure if it will couple to the primary correctly with it been
such a high coil ? I was thinking as a way around it to build a simple maggy
setup and just base feed the high coils.

cheers,
Chris





> Take care,
> Bart
>
>
>
>