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Re: Arc Load Match

Hi Terry,

> Original Poster: Terry Fritz <terryf-at-verinet-dot-com>
> 
> 
> Hi All,
> 
>     My Tesla coil model suggests something that may be rather interesting.
> Perhaps a bleeding edge experiment for the adventurous!
> 
> Since arcs appear to be capacitive at around 1pF per foot of arc.  It may
> be possible to add an inductor to the output to counter-act this
> capacitance and allow greater energy to be delivered to the arc.  I
> calculate that, in the case of my 110kHz coil, a 460uH inductor would
> cancel the 5pF of load capacitance of the arc.  This would theoretically
> allow 30% more energy to be delivered into the arc's resistance.  This
> inductor added between the top terminal and the arc would have to stand off
> the coil's full output voltage.  Thus, it's dimensions would be similar to
> the secondary but with far fewer turns.  The current would be small however
> (~1A).  Perhaps an inductor, suspended by nylon thread, could be connected
> to the top terminal and the arcs from the other end of the "extra coil"
> (I've heard that term before :-)) would be greater.  Perhaps the people who
> work with magnifiers know about this effect and could shed more light on
> this?  If someone were to have a spare large secondary form around perhaps
> an experiment could be performed.  I calculated (OK, MathCad did it :-))
> the inductances that would cancel 5pF at various frequencies below for
> reference.  The values would not have to be very exact at all.
> 
> Fo      L
> 100K        506uH
> 150K        338uH
> 200K        253uH
> 250K        203uH
> 300K        169uH
> 350K        145uH
> 400K        127uH
> 
> The reactance of a capacitor is:  Xc = 1 / (2 x pi x Fo x C)
> The reactance of an inductor is:  Xl = 2 x pi x Fo x L
> To cancel them:  Xc = Xl
> 
> I haven't tried this yet, so I really don't know what would happen...  I do
> wonder if the self capcitance and such of the extra coil may be a
problem?....

I suspect it might be self-defeating to a degree. However, I can't 
say for sure. Perhaps a test would be to place such an inductor in a 
target groundpath. I have stuck small coils on top of the terminal 
but not noticed anything unusual. They didn't have to hold off the 
entire secondary voltage. In effect they just seemed to add a bit 
more resonator to the resonator. Be interested if your expt does 
yield someting.

Malcolm