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Re: What efficiency?!
Tesla List wrote:
>
> >From MALCOLM-at-directorate.wnp.ac.nzTue Nov 5 22:30:12 1996
> Date: Wed, 6 Nov 1996 07:54:21 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: What efficiency?!
>
> Hi Richard, all,
> I would like to propose an experiment for a sparking
> machine that should be quite within the bounds of possibility for
> someone who has the gear. You wrote.......
>
> > I know of know person alive who has ever measured the actual output
> > efficiency of a Tesla coil! (what is this efficiency?- what are its
> > parameters-RF, Spark energy, magnetic fields, all?) I also know of no
> > form or process involving anything about the spark which will yield even
> > a +/- 20% correct answer to any question regarding same.
> >
> > I do know of a lot of proposed methods of measuring efficiency with none
> > of them having either been done, or if they have, a method of
> > verification or transfer to other systems which are vastly different in
> > character.
>
> How about setting up a grounded discharge rod for the secondary and
> measuring current both in the rod and at the base of the resonator
> simultaneously? A bridge configuration might show up any differences.
> The basic idea is to find out whether the curents are equal so we
> might have a basis for knowing whether the current measurement at
> the base truly reflects spark current (IMO it should) and thereby
> at least set one variable in concrete for further measurement. The
> reason I throw this open is that I just don't have the gear to do it
> myself.
>
> Malcolm
Malcom & all,
Based upon some of the measurements I made during the light-bulb
experiment, I'd suspect that the currents would be dramatically unequal
assuming you've got a large secondary discharger. Let's assume that we
discharge the top terminal through the grounded rod at a point near the
maximum secondary voltage excursion. The toroidal capacitor's "other"
plate is earth ground. If we now directly discharge the toroid to a
grounded rod, NO portion of this heavy discharge current is required to
flow through the base of the coil - we're directly shorting the cap!
Once we initiate this discharge current, the toroid/arc/groundpath
inductance form an LC circuit which oscillates in the 10-20+ MHz region.
The high inductance of the secondary will prevent most of this RF
current from making out the coil base.
During series resonance, the secondary base current is 180 degrees out
of phase with the toroid (capacitor) voltage. When we get the heaviest
"leakage" current from the streamers (at the secondary voltage peak)
should correspond to the current minimum of the series LC. Again, since
we're discharging primarily isotropic capacitance through the air while
attempting to hit ground via the streamers, I'd expect very little
direct correlation between streamer and secondary base current...
-- Bert --