Re: 15" coil project

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

Original poster: "G by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bog-at-cinci.rr-dot-com>

Malcolm,

You certainly have an excellent way of attacking a problem. Your 
original response struck a chord with me because when I was designing 
my current coil project, I tried to determine the maximum size of 
toroid I could drive without a breakout point. Being a student, I 
cannot afford to have duplicates of all the TC components, and I was 
simply trying to maximize my dollars spent and time scrounging. When 
I have a larger budget, I will likely refine a given setup to satisfy 
whatever goal I have in mind. Not to mention publishing my results 
for all to benefit! Thank you for all your research and contributions.

happy day,
Gregory

>
>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
>  >
>  >
>  >
>  >