Fr testing Was Re: Sphere/Toroid Comparison Chart

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi John,

I didn't suggest putting the resonant frequency as an input. I did suggest
"adjusting" Fr instead of Ctop since
indanctance and capacitance are probably both changing. But after further
thoughts, I withdrawel that
suggestion. It doesn't make sense to adjust Fr without either L or C doing
the adjusting. Your percent value
reducing Ctop is probably the best method right now.

Take care,
Bart

Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
>
> Bart, All -
>
> Regarding your suggestion for putting the resonant frequency in the inputs I
> tried this several years ago. I show a design procedure for Tesla coils
> using the resonant frequency as a start in the Tesla Coil Construction
> Guide. However, I soon found that this put a burden on the designer that was
> not realistic in most cases. When you make the resonant frequency an input
> you have to be able to predict the resonant frequency. The E-Tesla6 program
> can do this much better compared to a designer's estimate. Even a resonant
> frequency program will have some inaccuracy. Only a proper test after the TC
> is built will give you the actual resonant frequency.
>
> Once you have the actual test frequency you can then adjust the secondary
> terminal pf value to give this frequency in the outputs of the JHCTES or
> JavaTC programs. It is obvious that with the E-Tesla6 program you will be
> able to start with a more accurate TC design.
>
> If you want to take into consideration the effects of secondary inductance
> changes due to currents then you cannot use the Wheeler equation. Someone in
> the future may want to tackle this problem. The fundamental equation for the
> inductance of a wire is
>      L = Fl/I
> L  = Inductance of a wire
> Fl = Flux linkages
> I  = Current causing the flux
> I would expect it would be a difficult road to get from this equation to the
> design of a Tesla coil.
>
> I do not believe that the resonant frequency should be in the inputs for the
> JHCTES or JavaTC programs because the only way to determine this frequency
> is by test after the TC is built. After you know the resonant frequency then
> you can adjust the secondary terminal pf to give you the correct capacitance
> so the resonant frequency shows in the outputs. From this info you can then
> find how much the toroid isotropic capacitance is reduced when placed on the
> secondary coil.
>
> John Couture
>
> --------------------------
>
> ---Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, May 09, 2001 7:54 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Sphere/Toroid Comparison Chart
>
> Original poster: "Barton B. Anderson by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <tesla123-at-pacbell-dot-net>
>
> Hi John,
>
> Tesla list wrote:
>
> > Original poster: "John H. Couture by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
> >
> > Kurt -
> >
> > I agree the equations shown on my web site do not represent the table
> shown
> > below. However, for toroids above 20" large diameter there is a close
> > agreement. The graph I show in my books is based on my web site equations.
> > The graph covers toroids with large diameters from 10" to 80" and spheres
> > 10" to 60". There are straight line curves for 3"-6"-12" and 20" small
> > diameter toroids. None of the curves overlap.
>
> I also graphed my data. The linearity is definate. This is good news.
>
> > The equations were shown in the Tesla Coil Builders Association Newsletter
> > Vol 6, #2. The graph was made several years ago using the Quattro Pro
> > program. The graph shows isotropic capacitances which have to be reduced a
> > certain percentage when the toroid is placed on the secondary coil. I
> > estimated the percentage reduction should be about 20% but this may be too
> > high.
>
> I understand how you came to a percent based on your graph. This is good.
> However, 20% may not be too high. I
> think it will depend on many variables.
>
> I propose that both JHCTES and JavaTC should change Fr and leave Ctop alone
> (Fr is the affected parameter as
> you know - regardless of C or L changes - Fr is what counts). Why not make
> Fr the changed value. In all
> probable systems, it will be less than 20%. You could easily adjust your
> graphs accordingly to represent Fr (Fr
> "did" change to this value regardless of C or L unknowns).
>
> The programs can be more appropriately representative to real world coils.
> Later when C and L are better
> defined, the programs can more accurately represent these values and Fr
> should then be even better. Just food
> for thought - something to chew on. I'm sure you've been down this road
> before.
>
> > Terry's E-Tesla6 program will certainly give a more accurate
> > capacitance because it takes more of the surrounding variables into
> > consideration.
>
> I totally agree!
>
> Take care,
> Bart A.