Re: Toroid Modeling

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

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

Hi John,

Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<FutureT-at-aol-dot-com>
>
> In a message dated 8/29/01 10:13:36 AM Eastern Daylight Time,
> tesla-at-pupman-dot-com writes:
>
> > Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest.
> > net>" <tesla123-at-pacbell-dot-net>
>
> Bart,
>
> Your results are very interesting.  So I guess when the
> toroid is small, the shielding of the secondary dominates,
> and as it gets larger, ground plane effects of the floor
> begin to dominate.

Yes, I think the increased area (both distance and surface) of the toroid
see less
of the secondary and more of the ground plane. I'm not really sure if it's
both (it
may be simply proximity to the secondary).

>  It would seem then that as a coil is made
> larger, it should be made taller also, or at least higher off the floor,
> to reduce ground plane effects.  I guess the primary itself may
> act as a ground plane.  This may argue against the use
> of large diameter primaries.  Of course a coil with a large toroid
> is normally made taller anyway, otherwise the sparks
> would strike the floor.  As it is, a 20" to 24" toroid is probably
> larger than would be normally installed onto a 3" x 15" secondary.
> Your results should scale linearly I would think.  For instance
> if everything was doubled in size, for instance a 6" x 30"
> secondary, at twice the height, and twice the toroid size, etc,
> should give the same graph characteristics.  It would be
> interesting to do some graphs for various coil heights I would
> think, and also some graphs for existing coils, to see where
> they fall on the graph.
>
> Thanks,
> John

Yep, I agree. I think it's too soon to conclude anything yet, but as you
can see,
there are a lot of models to run to get an idea of how the toroid size
affects the
circuit values. The toroid sizes I'm using are purposely too small, about
right,
and too large. I'm trying to get an idea for various sizes. I definately
will run
many secondary ratios, but starting with 5:1 for now. I'm also trying to
close some
of the gaps in toroid diameters to smooth out the graphs. I'm just starting the
exersize and continually honing the data collection technique, but it's a slow
process. The nice thing is that anyone can do this for their own coil using
E-Tesla6. I think what should be realized at least at this time, is that
top loads
affect the system differently and measured frequency's will tell you how
much. One
of my goals is to get enough data to get a good idea of how much without
measurement.

Take care,
Bart