Re: 15" coil project

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Greg,
         I cannot say that I am a great believer in computer programs 
since they appear to be, for the most part, a more complex form of 
calculator which adds little in the way of "design" (my sincere 
apologies to those who consider their programs to be more than this). 
I have written a few small utilities for calculating Cself etc. and 
used a spreadsheet to demolish an old wirelength idea that was once 
popular but beyond that do not expect to be writing anything else.
      Below I suggested a range of qualities desirable in a coil 
which meets my personal coiling aims. To a degree it reads like a 
simultaneous equation. I previously suggested specifying output 
voltage and terminal energy which, together with a primary power 
figure, gives the starting point for such a design.
      Personally, I get more enjoyment from developing an idea than 
cranking out a rote design from a program.

Regards,
Malcolm

On 22 Oct 2001, at 17:59, Tesla list wrote:

> Original poster: "G by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<bog-at-cinci.rr-dot-com>
> 
> What a great idea Malcolm! I'd be glad to beta test your new design
program! :P
> Gregory
> 
> >
> >Unfortunately, it is difficult to separate the wheat from the chaff
> >so easily. Your conclusion takes only a couple of factors into
> >account. One not mentioned is the winding length, something to which
> >I would attach the utmost importance. My question is: was the voltage
> >handling capability of your two coils the same? (Bet = no).
> >
> >     On the question of wiresize and efficiency, a bunch of
> >measurements I did on a range of coils showed clearly that there is
> >an optimum sized topload for a given secondary and that if you start
> >with a wiresize that is too small, adding topload to the bare coil
> >will cause its Q to start diving. A more useful coil will have a
> >sufficiently large wiresize that causes its Q to go UP as topload is
> >added (until some point where it starts to go back down again as the
> >L/C ratio is dropping). An ideal coil will have a topload sized for a
> >peak in Q with the coil, a radius of curvature that puts it right on
> >the edge of breakout for the voltage being developed, a sufficient
> >height for the voltage being developed (to prevent flashovers), and a
> >primary surge impedance in the 50 - 100 Ohm range with sufficiently
> >large conductors in all primary components.
> >
> >Regards,
> >Malcolm
> 
> 
> 
>