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RE: New JHCTES Ver 3.0 TC Computer Program
At 04:27 PM 04/19/2000 -0700, you wrote:
Hi John,
>
>To All -
>
>I think I was a little hasty with that comment. There are many more
>important TC calcs that need to be addressed. For example, the Ver 3.0 does
>not take into consideration the energy flow thru the TC system. The default
>design in the program is for a 15 KV, 60 ma, 900 watt coil. The program
>gives all the info for keeping the system in tune but how about the the
>balance of the energy at the input, primary circuit, and secondary circuit?
Be sure to see my paper at:
http://users.better-dot-org/tfritz/site/papers/modact/modact.html
The information in the post at:
http://www.pupman-dot-com/listarchives/1999/June/msg00323.html
may also be what you seek...
There is also much thought being given to matching a coil's output
impedance to the impedance of the arc for maximum power transfer. Posts
like the following are of special interest (archives didn't have it yet).
This may also be of special interest to Duane Bylund too.
==========================
Hi All,
I have been playing with my patched together RF generator and measurement
equipment. Today I took off work early to do something important. ;-)) I
was able to measure the impedance of the brush discharge of my coil run
from the generator in CW (continuous wave) mode.
The secondary is 1180 turns of #24 wire on a 4.25 diameter PVC form 26.125
inches long with an inductance of 22.1mH (from my little 9kV/30mA coil).
The primary is 10 turns of 0.092 inch Litz that is 6 inches in diameter.
That is about 2uH. I used the generator to drive the coil at 100, 200,
300, and 400 watts delivered power compensating for the small reflected
power. All the coil components stayed cool so I assume almost all the real
power was going to the discharge. I can adjust the frequency to get the
lowest reflected power so it is very well in tune at each level. I ran out
of tuning range at 400 watts with the fiber optic probe transducer on the
top of the coil (added top capacitance). I will need to wind a new
slightly higher frequency secondary to get the generator's full 900 watts
forward power in tune with the probe in place. Hopefully, nothing will
melt down at that level...
It appears that the discharge is composed of a resistive region a few
inches in diameter (the part you see) that provides a relatively low
resistance path to a capacitive sphere around this discharge. Thus the
discharge is a real resistor in series with a capacitance around the discharge.
Obviously, I need to write one of my papers on this to fully explain all
the details, but for a point discharge at around 330kHz, I got a discharge
impedance of:
Z = 20K + 3K ohms / 100watts delivered (real resistance) in series with
0.58pF + 0.070 pF / 100 watts delivered (capacitance).
The actual numbers are as follows:
Delivered power Resistance Capacitance
100 22887 0.665pF
200 26122 0.754
300 29409 0.827
400* 30779 0.892
*The 400 watt measurement is messed up because the frequency dropped too
low for the generator to tune properly.
I know very little about CW coils (but am learning fast ;-)).
I noticed that this coil produces almost no ozone or other noxious fumes in
operation. I was very surprised by this! Perhaps all CW coils are ozone
free and I just missed that bit of info. Not gassing out the basement
during this testing is VERY pleasant as is the quiet discharge!! It is
very cool but does not strike the "fear" those big disruptive coil
streamers, gaps, and all do...
The current at the top and bottom of the coil are almost perfectly in phase
but there is about a 60nS shift. 20nS of this should be caused by the load
impedance having a slight angle (87.7Deg. at 640K) and perhaps the other
40nS is due to the very slight transmission line effects. Apparently, the
top and bottom currents in the secondary inductor of CW coils are just as
phase locked as disruptive coils. The last coffin nail for those old 1/4
wave wire length theories ;-))
Much more to come on all this but I wanted to let everyone know about this
fun project to this point. Obviously impedance matching, computer models
and all that will be greatly aided by such information. In many ways, CW
coils are far simpler than disruptive coils. I was very surprised that at
300 watts I was able to tune the coil with ZERO watts reflected (the
generator has a 50 ohm output through about 10 feet of RG-8). My primitive
computer models suggested such things but I didn't believe them...
Apparently, primary inductance is not at all critical but coupling is...
Of course, the RF generator is much more predictable than tubes (at least
for me)...
Much much fun was had today! ;-)))
Cheers,
Terry
==========================
>
>The default design energy input is 900/120 = 7.5 watt secs per bk (bang).
>How is this energy distributed in the primary and secondary circuits. The
>basic equation is .5 * C * V^2. What kind of efficiencies should be used
>to make this equation conform to the real world? I would be interested in
>any comments from the List.
>
>I am also waiting for someone (not me) to write that super book on Tesla
>Coils. There are some coilers on the List that are capable of writing that
>book but obviously don'thave the time.
It is hard to write "THE book" while things are changing so fast. However,
there is no doubt that all the current books are quickly falling behind the
many new things that have come about in the last few years.
MMCs, MicroSim modeling, the "glorious victory of lumped secondary theory"
;-)), powerful new measurement techniques, and just the shear power of
having us all here together here on this list to work on things together
with bazaar speed has drastically changed the state-of-the-art of Tesla
coiling. New ideas can literally be put to the test in hours with state of
the art equipment. New ideas can no longer just be "put out there" and
everyone will believe it. There are now a number of people all over the
world who can quickly repeat experiments and confirm or deny results within
a day. My recent "poor" transmission line experiment was repeated by
others in a day and the errors were reported and I could quickly realize
and correct the mistakes within the next day. I shudder to think how long
I could have gone with that incorrect mess without others steering me back
to reality. 10 years ago, that process could have taken a year or two!
We also have a large number of people who are highly expert in a wide
number of related disciplines who can jump in and help us out. The recent
thread about pacemakers and Tesla coils was helped drastically by doctors
who have first hand experience with these devices as well as people with
them implanted who had gotten too close to Tesla coils! No arm waving
guess work stands a chance in this powerful environment.
So who is going to write that book?... Sooner or latter one of us will...
Just a matter of time and inspiration...
Cheers,
Terry
>
>John H. Couture
>
>--------------------------
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