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RE: The 1500t secondary myth (long)

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Steve,

At 03:54 AM 12/2/2004, you wrote: 
>I haven't been following things enough to see where the 36k came from

I worked it out in the following way- According to Terry the impedance of
streamers is 220k (irrespective of the length) in series with 1pF per foot.
So as the length of a streamer tends to infinity, the impedance tends toward
a resistance of 220k. It sounds counter-intuitive but in my own experimental
work I've not found anything that would disprove this.

Interesting! Although the 220K + 1pF/foot thing was sort of a wild guess based on models and observations, It does seem to be standing up well over many years now. The streamer is dynamic, but it does always seem to following this model fairly well... Even though there is no direct basis for it, there bust be some odd "truth" there...


And Malcolm Watts argued that the loaded Q of a Tesla coil can never be less
than 6. He predicted that if you try and design one with Q<<6, the streamers
would just shrink to restore the Q to 6.


Loaded coils have low Q for sure...


Again this agrees with experiment. It's particularly obvious with SSTCs: as
you drive them harder you reach a point where the system doesn't accept any
more power and the streamers don't get longer. At this point, the only thing
that will give more spark length is adding a bigger toroid (ie lowering Zo)

Note: this is not a quantitative proof because SSTC streamers probably have
a lower resistance and higher capacitance than Terry's 220k/1pF formula
which was for disruptive TCs. But qualitatively it seems to back up my
argument.

Putting these two constraints together means that the Zo of the resonator
should be about one-sixth of 220k. This will guarantee that streamer length
is never limited by running out of Q.

We are sort of grasping for little clues and things that help us predict further into the unknown. It seems we are fairly good at it really!! We can't solidly explain it, but by using these odd tools we learn more and it does prove out in the end. The first thing I ask Dan was if the model formula seemed to work on the DRSSTC case. It did and pretty well ;-)) Don't know why, but can't look a gift horse in the mouth ;-))

Cheers,

        Terry




Steve C.