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Re: well, this is interesting

Subject:   Re: well, this is interesting
  Date:    Mon, 5 May 1997 12:36:27 -0400 (EDT)
  From:    Chip Atkinson <chip-at-XiG-dot-com>
    To:    Tesla List <tesla-at-pupman-dot-com>


On Sun, 4 May 1997, Tesla List wrote:

> Subject:  well, this is interesting
>   Date:   Sat, 3 May 97 05:02:48 UT
>   From:   "William Noble" <William_B_Noble-at-MSN.COM>
>     To:  "Tesla List" <tesla-at-poodle.pupman-dot-com>
> 
> 
> well, I learned a few things tonite - maybe even some make sense.  I
> added 
> some capacitance to my new coil - I started from .001 mica and added a
> .001 
> 14.5KV capacitor made by Plastic Capacitor company (it's about 1"
> diameter, 8 
> inches long, encased in glass) - sparks went from dinky little 3 inch
> sparks 
> to really nice looking 18 inch sparks with lots of forking.  So, adding 
> capacitance is good, and the little Plastic Capacitor unit is good too -
> it 
> warmed up just a bit in a 20 to 30 sec run (about as long as I can run
> with my 
> half done RQ spark gap with no fan) - it felt like it raised up about 5 
> degrees or so.

It sounds like you had your system tuned to a different harmonic rather
than the fundamental one.  Tesla did this, or at least reported on it. 
He
talks about it in the Colo. Springs Notes on July 27th (+/- 2 days). 
The
result was that tuned at an "octave", rather than the fundamental
frequency yielded much smaller sparks.  The one thing I wonder about
though is why you didn't get breakout in the middle of your coil.


> 
> I also learned that the toilet float I used for a top capacitor (a
> plastic one 
> with some aluminum foil wrapped around it) keeps a charge - I got a
> small 
> shock when I went to dismantle the coil - I don't quite understand this
> since 
> I thought it would be grounded through the secondary (the low side of
> which is 
> grounded), but the connections were't the best, so maybe there was an
> open 
> circuit???

There was a long discussion a while back about the nature of capacitors. 
There appeared to be two factors.  Charge on the plates, and
stressed/charged dielectric.  I believe that the coating of your coil
(even if you didn't coat it, the wire is still coated with insulation)
is
charged/stressed.  When you touch your coil, your hands collect the
charge
and conduct it to ground (or a lower potential), which involves the rest
of your body as a conducting path.

The other interesting feature of a shocking coil is that you can get
multiple shocks.  Just rub your hands over different parts of the coil.
You'll get bunches of nasty static shocks.

The way I found to get away from that is to "wipe" the coil with a
grounded wire.  I have a small flexible wire that I hold around about
1/2
the coil's diameter and move it up and down, and around the back side as
well.  I can hear little crackles as sparks jump to the wire.

I believe that the static problem goes away as you get your coil tuned
better.  I found that when the sparks were really cranking out, the coil
didn't get charged.

> 
> What I don't understand is the following - when I doubled the tank 
> capacitance, I would have thought I would halve the tank inductance to
> keep LC 
> about constant and maintain resonance with the secondary.  But I found
> that 
> with .002 uf it was best on turn 13 (I only have 14 total turns on a 1/4
> inch 
> {50 ft} tubing flat spiral primary), and with just the .001 mica
> capacitor it 
> seemed to like fewer turns - my notes say that with the same secondary 
> configuration (toilet float on top, etc) I got best performace at turn
> 8, and 
> with no top capacitance, best was at turn 13.  does this make any
> sense???
> 
> And, can I expect still better performance by adding more primary 
> capacitance?? (input xformer is 15KV 30 ma neon) - it would seem so....
> 

Up to a point.  There are two things to consider:  The frequency must be
correct, which is affected by the capacitance, and that your transformer
can charge up the capacitor.

Chip

---------------------------------------------------------------
First Corollary of Taber's Second Law:
        Machines that pperturb people often get murdered.
               -- Pat Taber
---------------------------------------------------------------