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RE: JHCTES Ver 3.1 Program
I thought I had covered your concerns about the Ver 3.1 program in our
previous private emails. Apparently you did not understand what I was trying
to point out to you. I will explain further.
The website you refer to is recommending a primary capacitor of .005 uf for
your 15 KV/30 ma NST. This can cause your NST to operate in the resonant
charging mode and could destroy your NST and is the reason I do not
recommend this size capacitor. Apparently the website author is unaware of
this hazard and does not warn his readers.
Start the design process with the secondary circuit before the primary
circuit as I recommend in my "step by step" post to the Tesla List of June
3, 2000. Then design the primary circuit. The recommended size for the above
primary capacitor is shown in a graph in one of my books. When this
capacitor is changed the computer will change the primary coil turns so the
TC system will stay in tune.
The Ver 3.1 will show you the correct spark length provided you enter the
correct current in the program input. Your NST will produce a larger than
rated current in the resonant charging mode and this current will have to be
metered and entered into the program input. However, I understand you are
not designing a classical Tesla coil so this program should not be used.
John H. Couture
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Monday, June 05, 2000 9:32 PM
Subject: Re: JHCTES Ver 3.1 Program
Original Poster: "Richard Kircher" <richard.kircher-at-worldnet.att-dot-net>
We've emailed before. I suspect your program still does not have a way to
start the Tesla Coil design process by coming up with the primary capacitor
size. If you would like to overcome this limitation, there is an excellent
web site at
that will fill this void in your program. It tells you how to compute the
optimum capacitor size from the transformer ratings.
In testing different programs that do this computation, I have gotten two
answers for a 15,000 volt 30 ma NST. The answers are .005 uF using
Ntesla17 (my favorite), and .00375 uF using another pragram (don't remember
which). I finally wrote a simulation (easier than closed form solution)
and it turns out that both are correct in terms of the joules stored over
the charging time period, but the .005 is better because the spark gag size
and quench time is less critical.
As I suggested before, your program is very miss-leading on spark length
which is a function of energy stored in the cap. To someone that does not
understand this and just wants to use the program to cookbook a coil, there
is major disappointment ahead. Your program gives the same length spark
regardless of capacitor size and that is wrong since someone could build a
TC using a .000000001 cap and then find out after construction that it
provides no sparks at all! Any size transformer with a small cap won't
work and there is an optimum size. This is why most programs provide this
If I can be of help in offering the computation method or simulation
results, just let me know. I would be glad to help. Your program seems to
be based on a wealth of empirical data and just needs a little help in this
area to be really great.
At 07:42 PM 6/3/00 -0600, you wrote:
>Original Poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
>To All - ..............
>I would be interested in your comments to improve the program.
>John H. Couture