Re: Tesla Coil toroid Size

To: tesla-at-pupman-dot-com
Subject: Re: Tesla Coil toroid Size
From: Richard Hull <rhull-at-richmond.infi-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Wed, 16 Sep 1998 18:59:32 -0600
Approved: terryf-at-verinet-dot-com


Tesla List wrote:

> Original Poster: Greg Leyh <lod-at-pacbell-dot-net>
>
> Here's an example:  My primary capacitor is 0.225uF, and operates at
> 26kV.
> The Vpri is *not* adjustable in this design, which means that the Ep is
> independent of the break rate, and therefore is always 76 watt-seconds.
>
> At a BPS of   1, the sparks at the toroid are about 2.5 ft long.
> At a BPS of  80, the sparks at the toroid are about 4.0 ft long.
> At a BPS of 350, the sparks at the toroid are about 25. ft long.
>
> The coil gains a factor of 10 in spark length while the energy
> per pulse in the primary remains constant, at 76 Joules!
> The dramatic increase in spark length is due solely to the coil
> exploiting the ion lifetimes at the higher break rates.  The
> coil *DOES NOT* generate higher voltages at higher BPS values.
> --
>
> -GL
> www.lod-dot-org

All on this list need to realize the above is simply a fact!!

 The coil, other than supplying input energy in convenient packets and
breaking
down the air with some voltage "V" is out of the picture other than as a
pulsed
source of energy to a formed or forming ionized gas arc channel.

In any fixed system, once the BPS hits some critical value for the enrgy per
pulse and has a nice field control via a large toroidial top load, the ion
lifetimes are longer than the interval between pulses.  The channel will
grow to
longer lengths with a specific input energy rather independent of voltage
over a
narrow range.  Thus, an attached long hot arc may remain attached for seconds
while the Q of the coil is sinking to near zero along with the idealized
terminal
voltage!!!

This is a commonly observed air pressure arc phenomena.  120 volts will not
arc
over even a fraction of a millimeter, yet carbon rods might form a drawn
arc once
momentarily connected and then separated of 6-8mm!  It is the ions in the
hot arc
that keep the arc going not the voltage across the arc which might now only
be 20
volts provided suitable heater balasting is supplied.

The lowering of the base impedance by the toroid even with attendant Q
reduction
is far more valuable to longer arcs than any voltage maximum achieved on the
system terminal by large Q.  The highest Q systems have no Toroid!  They also
produce abyssmal performance and can't ever handle any real power.  Also,
field
shaping and control afforded by a large terminal are most benificial in
allowing
small resonators to perform amazing feats and handle huge energy levels.

You tell 'em Greg!

Richard Hull, TCBOR