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Re: Primary and Secondary winding direction



Original poster: "Dr. Duncan Cadd by way of Terry Fritz <twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>

Hi Paul, John et al!

Date: 07 January 2001 22:57
Subject: Re: Primary and Secondary winding direction


>Original poster: "by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <paul-at-abelian.demon.co.uk>
>


<snip>

>I fail to see how it can have sufficient
>relevance to warrant its use as a basis for toroid
selection when in
>view of energy storage the smallest possible toroid ought
to be
>desirable. In what sense is the performance optimised - not
for output
>voltage, obviously - and which performance measures
deteriorate when
>the toroid is increased or decreased from this optimum
size?
>


For spark transmitter-driven coils, the largest secondary
capacitance is desirable.  You might want to modify that
with "and which will give spontaneous breakout".  This is
because the energy stored is equal to 0.5 q^2 / C and the
bigger the secondary capacitor, the larger the charge q
stored on it for a given energy, i.e. as capacitance goes
up, so does the number of electrons in the bottle for a
given bang size.  It's the charge on the secondary terminal
i.e. the number of electrons which does the damage, rather
than the voltage across the secondary which is necessary to
get it there.  The charge on the terminal then generates its
own electric field, E = q / (4 pi E0 r^2) where E0 is the
permittivity of free space and r is in metres measured from
the centre of the sphere (or the centre of the minor
diameter of the toroid) and E is in volts/metre.  When E is
around 2-3 megavolts/metre at the surface of the toroid or
sphere (or whatever) then the air breaks down and you get a
spark.  The charge will determine how big - it'll be an
equilibrium of forces calculation I'm certain, but haven't
worked it out yet.  The potential at a distance is simply r
times this, i.e. V = q / (4 pi E0 r) in volts.

See my article
http://home.freeuk-dot-net/dunckx/wireless/scotty/scotty.html

Any comments on the theory welcome, and thankyou to those
who have responded re the site generally.

Dunckx