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Re: Arc length vs pwr
Hi Robert, all,
> > On tuning: there is one subtlety I have used where Lp and Cp are
> >more-or-less fixed: raising and lowering the top terminal can
> >dramatically alter secondary fr.
> >
> >fwiw,
> >Malcolm
>
> Malcolm, Richard Hull, All,
>
> One thing I've noticed playing around with the height of the final
> large toroid above the secondary in my MTC system is a tendancy to
> produce more strikes to earth with the toroid closer to the secondary, and
> seemingly more streamers shooting outwards or straight up in the air with
> the toroid placed 3 inches higher. I have only one test run under my
> belt where I seemed to notice this effect and at the time I chalked
> it up to an effect of varying the e-field control, but perhaps there
> is more in this? If the Q has been changed, the theoretical final
> voltage will be changed as well, although this becomes clamped to whatever
> as soon as a streamer appears, _ BUT_ , the voltage gradient at the surface of the
> toroid _IS_ determined by the field shaping and therefore will alter
> to some degree the breakaway voltage for a given radius of curvature toroid.
>
> So by varying the height above the secondary we are not only
> changing the voltage developed by the change in Q, but we are
> changing the breakaway voltage of the toroid by the change in
> electrostatic field control around it. Isn't it nice trying to
> analyze several interwoven variants changing at the same time?
<snip>
Q does indeed change. But the resonant frequency can change
dramatically as well because it changes the total capacitance of
the system. We had a discussion on this some time ago. I also took a
bunch of measurements late last year with disks mounted at different
heights above a number of coils. I'll post them to you offlist if you
like. Ed Phillips coined the term "mutual capacitance" to describe
this effect. The terminal is not isolated and floating free in space
so its capacitance is never what theory might suggest. An interesting
trap that Tesla might possibly have fallen into when measuring Cterm
with a sphere at different heights is that the wire leading to the
terminal can add greatly to the capacitance as well! You can see this
if you add a few feet of stiff wire to your discharge terminal and it
shows up dramatically in the L/C ratio of a vertical monopole.
Thanks for posting your observations on discharge types. I will
make special note.
Regards,
Malcolm