Re: Tesla's CS Coil Data from ScanTesla and all....

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 02:05 PM 6/26/2005, you wrote:
> Original poster: "Chris Rutherford" <chris1@xxxxxxxxxxxxxxxxxxx>
>
> Hi Terry,
>
> I think Tesla knew what he was doing, and he has mentioned on several 
> occasions the need for a properly tuned system, indeed I find it hard to 
> believe that he would have been able to generate 100ft streamers by simply 
> throwing more power at it.
>
> "The adjustments are such that the reservoir is filled full and bursts at 
> each alternation just at the moment when the electrical pressure reaches 
> the maximum. The discharge escapes with a deafening noise, striking an 
> unconnected coil twenty-two feet away, and creating such a commotion of 
> electricity in the earth that sparks an inch long can be drawn from a 
> water main at a distance of three hundred feet from the laboratory.
>
> I have produced electrical discharges the actual path of which, from end 
> to end, was probably more than one hundred feet long" - Probelm of 
> Incresing human energy Tesla.
>
> Assuming 100ft = 40 Meters and dialectric breakdown of air is  3 x 10^6 
> V/m then that would mean a potential of 13.3MV.
>
> Is he making this up, or are we missing something important here?
>
> Thanks
Chris, you're probably going to get a bunch of responses to this.  You've 
made some assumptions that aren't necessarily valid.

1) The "hundred foot spark" claim does NOT mean from one electrode to 
another being 100 feet.  I don't recall the entire history of the claim, 
and it's repetition in innumerable subsequent biographies and reports, but 
most likely, it's a) estimated; b)accounts for all the wiggles and 
sinuosities; etc..

2) The 3MV/meter breakdown for air is in a uniform field gap.  The field 
around a TC is nowhere near uniform.  Furthermore, as soon as the spark 
starts to form, the spark itself changes the field (it's a fairly good 
condctor, at least compared to free space).  The widely accepted theory of 
spark growth (at many scales, from little lab sparks to lightning) is that 
the spark grows in little jumps, "breaking out" from the end of the already 
existing spark channel.  That spark channel is quite small (even lightning, 
which is very high current (10s of kA), only has a spark channel that is 
some 1-2 cm in diameter), so it has a tight radius of curvature, resulting 
in a fairly high E-field that can exceed the 3 MV/meter breakdown.

3) Tesla coils actually combine many successive breakdowns in one spark 
channel, extending it on each cycle.