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RE: Sphere/Toroid Comparison Chart

Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

Hi John,

At 12:57 PM 5/8/2001 -0700, you wrote:
>Terry -
>I entered your coil's data into the JHCTES Ver 3.2 program to see what it
>comes up with for a toroid. To get the 87.66 Khz the program came up with 29
>pf for the capacitance. This is about 12% less than the graph shows (space
>33 pf) for an 8 x 30 toroid. On my web site I mention that the graph
>capacitance would be reduced about 20% when placed on the TC secondary. It
>appears this may be too high a percentage. We will have to wait until more
>data is obtained.

Of course, I like "my" program's answer :-))  The program seems to be
running at about 2% accuracy but can often get to within 1%.  One thing
that does make a big difference is the size of the room the coil is in.
E-Tesla will take into account the coil being in a small room and such.  I
am not sure how your program works so I can't suggest too much.  Paul's
program uses a similar technique too but I have never made any comparisons.
 Thankfully, all the programs now seem to be close enough for coil design
work.  Such a small error is easy to fine tune in any case.

>Did your coil test about 87 Khz when it was operating? Did you test the
>secondary with toroid by connecting a funtion generator to the bottom of the
>secondary? I don't remember seeing this information on your web sites.

No!  Mine is the non-streamer function generator frequency.  If your
program is taking into account streamer loading that could easily be the
difference.  I typically use MicroSim which adds streamer loading effects

>I was able to run the E-Tesla5 version OK but I get a "bad command" message
>when I try the Ver 6. Have other coilers had this trouble? I agree that your
>E-Tesla5 is an excellent program and is a great supplementary program for
>programs like the JHCTES for finding the actual secondary terminal

I have not heard of this problem before??  I can't think of anything that
would cause this error.  If anyone else has this problem or knows what it
may be, please write me.  There is not too much real difference between
versions 5 and 6.  There may be a problem with the "input.txt" file so
renaming that file to some null name may help.  It should run fine in the
DOS box under Windows.  If you are running pure DOS alone that may be a
problem but I don't know for sure?

>The secondary terminal capacitance is an input for the JHCTES program but
>only a graph with a rough capacitance approximation is given. A much better
>capacitance approximation is now available when coilers use the E-Tesla

The terminal capacitance on the actual coil has always been a real problem
to predict that E-Tesla was meant to fix.  After a year it finally achieved
that.  The other one was calculating the coupling of a coil before it was
built.  Mark Rzeszotarski and now Paul Nicholson have given us programs to
do that.  so we have some wonderful tools now to fill in some of the rough
spots in designing coils.  The output streamer impedance is roughly
220kohms + 1pF per foot of streamer length but hopefully that rough
estimate will be improved upon too in the near future.

E-Tesla6 is free and public domain with the source code in the zip file so
that anyone who wants may freely use it in other programs as they please.
there are no strings attached.  

I would also like to thank once again the many "real" programmers who
helped make the program so fast and nice compared to the original BASIC
program I cobbled together.



>John Couture
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Monday, May 07, 2001 9:56 PM
>To: tesla-at-pupman-dot-com
>Subject: RE: Sphere/Toroid Comparison Chart
>Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>Hi John,
>"E-Tesla6" a program I wrote that was vastly improved by others, can find
>the resonant frequency of a one or two torroid (or sphere) Tesla coil
>secondary system within a percent or two.  It does all the nasty
>electrostatic field calculations and even has elements of Paul's TSSP
>project added.  It is freely available at:
>A web page with info is at:
>It is very useful for determining the resonant frequency of a secondary
>coil and top terminal before they are built.  Everyone seems to like it a
>lot and it seems to work very well.  I ton of effort went into the darn
>thing ;-))
>	Terry
>At 09:48 PM 5/7/2001 -0700, you wrote:
>>Bart -
>>My graph was strictly a one toroid only graph. Note that all these space
>>capacitances are reduced when the toroid is placed on the secondary coil.
>>Just how much reduction can only be found by actual tests while the TC is
>>operating. Or you can use the JHCTES Ver 3.1/3.2 programs to find the
>>capacitance if you know the operating frequency.
>>John Couture
>>-----Original Message-----
>>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>>Sent: Monday, May 07, 2001 7:10 PM
>>To: tesla-at-pupman-dot-com
>>Subject: Re: Sphere/Toroid Comparison Chart
>>Original poster: "Barton B. Anderson by way of Terry Fritz
>><twftesla-at-uswest-dot-net>" <tesla123-at-pacbell-dot-net>
>>Yes John, but does you graph indicate the same compacitance as was posted
>>for overlapped toroids? I'm guessing
>>it doesn't because Bert Pool's equation calc'd exactly as was posted on
>>these toroids.
>>Tesla list wrote:
>>> Original poster: "John H. Couture by way of Terry Fritz
>><twftesla-at-uswest-dot-net>" <couturejh-at-worldnet.att-dot-net>
>>> The overlap is not a problem with the Toroid Capacitance Graph I show in
>>> Tesla Coil Notebook because I did not use Bert Pool's equation. The
>>> equations I used are shown on my web site. Look for  Secondary Terminal
>>> http://home.att-dot-net/~couturejh/
>>> John Couture