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Re: spark energies
Tesla List wrote:
>
> >From hullr-at-whitlock-dot-comThu Oct 31 22:48:03 1996
> Date: Thu, 31 Oct 1996 17:57:25 -0800
> From: Richard Hull <hullr-at-whitlock-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: spark energies
>
> I just got to thinkin' deeper over a "samich" at lunch. In my post on
> spark energy, I would literaly have to account for all energies created
> by the sparks themselves in my scenario.
>
> Help me out guys.
>
> I have tried to think of all the posibilities, but doubt I have covered
> them all. A mental conclave might be in order. I have also opted for a
> large 15" spherical lucite ball which I have as the sparking chamber.
> This material is a poor conductor of heat and a blanket of R-19
> insulation over the ball should trap most of the heat within provided
> quick mesurements are made. I hope to use my little 15VA coil system on
> this one.
> I will, unfortunately, be unable to use a toroid in the chamber due to
> its thermal mass screwing with the air temperature. A small tungsten
> pointed needle will be the discharge point. (low thermal mass).
>
I think the major problems with this approach are that you would get
breakout at a much lower voltage than with the toroid, and the lack of a
toroid would decrease the efficiency of the resonator. Calibration of
the apparatus could be done by using a small resistor and a calibrated
current to measure the rate of rise of temperature versus time for given
input power levels.
>
> As the spark rips through the air it disappates its energy in the form of
> light, noise, heat, and ion production (which ultimately winds up as heat
> as the ions recombine). In air, sparks produce little RF energy, but a
> grounded arc channel produces short waves at a prodigious rate. (must
> avoid spark hits in my test).
I agree.
>
> I believe that the light and noise are a very small component and in a
> sealed chamber, a lot of the more energetic light, (uv), will ionize the
> local air anyway and a large portion of these ions will be placed in the
> chamber in the form of heated air as these, in turn, recombine.
> Electrical, resistive, heating of the arc channel is the bulk of the
> energy dissapated, although the ions produced by this little coil have
> been shown by me to account for a very healthy amount of energy. Again,
> If I can just let them recombine in the ball enclosure, all will go to
> heat. I am a little concerned that the ball will become dielectrically
> charged and the energy from the ions producing this charge will
> ultimately leak out to the outside air as soak through charging as in
> series capacitor units.
Again, your assumptions sound reasonable...
>
> By the way, I plan on scoping the input voltage across the transfomer on
> one channel "A" and the current via a Pearson wideband 1844 CT on channel
> two "B" and create a third mathed channel of A X B for a true time/energy
> plot on my tek TDS 340 digital scope so that I have a real handle on what
> went in. I'll use my K type thermocouple meter by Precision to take the
> before and after rectal temps on the fixed volume of air within.
>
> Another problem... the air is trapped and not circulating and will skew
> the results in some fashion, I am sure. But, still, this is the best I
> have heard of being attempted in this area, yet.
>
As long as the location of the heat source is relatively constant, the
ball relatively well thermally insulated, and the pickup has fixed
location, small thermal mass, and previously calibrated with resistive
heat source in same location as the discharge, this should be OK.
> I picked up on all this here in our lab two years ago when running
> Nemesis at 13KVA resulted in noticably increased air temps after long
> runs.
>
> Any thoughts on this guys! Really good experiment is never easy to make,
> especially if you plan on having anyone take your results seriously.
>
> Richard Hull, TCBOR
Some other thoughts:
It actually may be easier to measure/calculate the isotropic capacitance
of the output, and make a capacitive voltage divider (similar to that
shown in Duane Bylund's Modern Tesla Coil Theory Supplement, pp. 22-24).
If we know the degree of re-tuning necessary to get peak performance due
to ion cloud capacitance, we can recompute the apparent isotropic
capacitance of the toroid and ion cloud. With the calibrated voltage
divider, we can determine the actual output voltage under discharge
conditions AND the average Q of the secondary under heavy discharge
conditions.
Assuming we've got a toroid with a large curvature, we should also be
able to measure the Q of the secondary just prior to breakout, and the
maximum output voltage without breakout, which would give us a measure
of the maxiumum secondary energy available per bang (using 1/2(Ct
+Cion)Vs^2). Since the difference between the two Q's is due to energy
lost/cycle to the corona, we should be able to fairly closely estimate
the total energy lost per bang in the discharge alone. If we know the
PPS rate, we can calculate the actual average power being dissipated by
the secondary discharge. The advantage of this appproach is that we
could do the measurements/calculations at a variety of power levels up
to full multi-kilowatt levels.
Finally, we could make a hot-wire ammeter to measure the "average"
current flow of the corona discharge (like the earlier light bulb
calculations??). Coupled with the voltage divider measurements, we
should be able to compute the average power dissipated by the corona
discharge. I need to think about this a little bit more...
Speculative measuring to ya!
-- Bert --