Bonsai

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Original poster: "Herbert Mehlhose by way of Terry Fritz <twftesla-at-qwest-dot-net>" <herbert.mehlhose-at-kdt.de>

Hi all,
last weekend I finished my new coil model. I call it BONSAI because of
its size: secondary diameter is only 3cm, about 1.2inch, toroid diameter

is 12cm (4.8 inch). You can see a description on my homepage:
http://home.wtal.de/herbs_teslapage/index.html
Go to the link "Model 3".

There are interesting points I found:

1. The coil performs quite well, (streamer length of 6inches and more)
although
its frequency is about 1MHz and power is very low. I had expected less
due to high losses
because of this high frequency and low power.

2. As BONSAI only has very low power (using a 7.5kV/50mA NST) and a
2.2nF MMC
cap made of  10 PHILIPS KP/MMKP 376 caps, I tried to use the coil in my
apartment
where I do NOT have an RF ground (my larger models are used in the
garden of my mother,
where I have built an RF ground, but it is always 100km to drive there).

Although I do not have an RF ground, the performance seems not to
suffer. I also
noticed this on other tests with my Model 1b. Maybe RFI may be an issue
but also
for this, I did not find a real increase, at least for TV sets or radio.
I will also do tests with
BONSAI using the RF ground, when I will visit my mother next time.

3. Instead of an RF ground, I only used a vice, normally used for table
mounting
and connected the secondary base to it. A brass rod clamped in this vice
has been used to
draw the streamers (putting it far away causes the toroid to discharge
into the air).
This way I built a "closed ciruit" for the streamers: Current drawn from
the vice, going up
the secondary to the toroid and from there to the brass rod back to the
vice ....
When firing the coil, this vice draws continous sparks to the floor
where it is lying on. Even the
isolated wire, connecting the secondary base to the vice shows some kind
of corona to the floor
without burning any holes. See the pictures on my homepage...
How can this effect be explained? For drawing sparks or corona effects,
I think there is a potential
difference needed. Where does this come from in this case? Some kind of
capacitive effects
which work well due to the high frequency?
All in all, my impression is, that I have still a big lack of
understanding. Looking forward to
learn again....

Tell me what you think about BONSAI, and thanks you for any ideas,

Cheers,
       Herb