RE: Do these numbers look right?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "John H. Couture" <couturejh-at-mgte-dot-com> 


JC -

Thank you for your interest in the JHCTES TC computer program. This program
has helped many coilers over the past years. This is the granddaddy of
automatic tuned Tesla coil design programs. Note that Bart's JAVATC program
is a similar program and will give you more parameters and options. The
important feature of these programs is that they automatically keep the TC
system in tune when changes are made. This was not always true. In the past
a designer could end up with an untuned TC design using some of the
available programs.

There are a few interesting tricks you can do with the JHCTES that gives you
some important parameters. For example you can take any tube and wind a
large number of turns on it for a new secondary coil. With only an ohm meter
and JHCTES program you can find the inductance, coil self capacitance,
resonant frequency and number of turns for this potential secondary coil.

Another neat trick is finding the true capacitance of a toroid when placed
on the top of a Tesla coil. It is a well known fact that the toroid
capacitance changes when placed on the TC because of the capacitive effects
of the surrounding objects. These effects are difficult if not impossible to
model accurately. However, after the TC is built the change in the toroid
capacitance can be found by tests and the JHCTES program. Terry's ETesla
program can also find this toroid capacitance. An interesting research
project for a coiler is to calculate the toroid capacitance using Terry's
ETesla program and then compare these results with the test and JHCTES
program results.

The JHCTES program also allows you to find some unique TC parameter
combinations. For example how do you change the coupling factor of your TC
without changing the primary to secondary spacing or raising/lowering the
secondary? This can be done by changing the TPI or number of secondary
turns. The JHCTES program will give you these changes for any coupling you
desire and also give you many other parameter combinations.

Start the TC design by selecting the secondary radius, turns, and TPI
parameters.
When you click "Calculate" this will give you the approximate resonant
operating frequency. If you leave the Secondary Terminal = 0 the resonant
frequency will be the same as the ohm/JHCTES test.

The primary spiral is designed to be in tune with the secondary resonant
frequency. Enter a primary capacitor value. Start by drawing a rough sketch
which shows the primary inside and outside radiuses. Make an estimate of the
number of turns. This will give you the approximate average radius (input)
for the JHCTES program.  The primary spiral width (input) is adjusted to
give you the desired center to center (c/c) spacing for the turns.

The JHCTES program can teach you a lot about Tesla coil design. Have fun.

John Couture

-----------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, February 17, 2004 7:03 PM
To: tesla-at-pupman-dot-com
Subject: RE: Do these numbers look right?


Original poster: JOSEPH CACCIATORE <jocatch-at-us.ibm-dot-com>


Thanks John. BTW, nice program. Will use it to help verify and play with
the numbers. It is one of the nicest on line programs I have seen.

It is funny trying to limit the coil to a 5:1 ratio and 20" when the PVC
pipe I bought is 12' long and cost less than $5.  8-) 8-)

JC




"Tesla list" <tesla-at-pupman-dot-com>

02/17/2004 03:13 PM
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Subject
RE: Do these numbers look right?




Original poster: "John H. Couture" <couturejh-at-mgte-dot-com>


Joseph -

Note that 765 turns divided by 20 inches equals 38.25 turns per inch, too
large. The typical TPI for # 22AWG is 36.6 so you will have 20 times 36.6
equals 732 turns. The JHCTES computer shows 276 Khz res freq with the 4 x 24
toroid and 576 Khz without toroid.

With a .007 uf pri cap the pri will be about 12.1 turns and this will reduce
to 7.4 turns with increasing pri cap to .02 uf.

You can get more info by clicking

      http://www.miramar.sdccd.cc.ca.us/faculty/jcouture/tesla/jhctes33.asp

Enter

Primary   .007   5.5   0   4.5

Secondary   2   732   36.6   0   26

John Couture

----------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Monday, February 16, 2004 7:08 PM
To: tesla-at-pupman-dot-com
Subject: Do these numbers look right?


Original poster: JOSEPH CACCIATORE <jocatch-at-us.ibm-dot-com>


Hello again. I am well on my way to designing my first TC after giving up
trying to restore my old PE magazine coil from 1964. I checked and there
are a slew of programs and spreadsheets written to help design a TC.
Unfortunately some give different results for the same input conditions.

The program I found to be extremely helpful is an Excel spreadsheet called
the Tesla Coil Designer 3.0 by Ed Sonderman and Corey Ruch. It is great
because you can adjust the secondary/primary parameters and watch for when
they come in sync.

But never trusting any program fully (i.e., Tax Deluxe say I had an extra
$1800 coming back on my tax return, it was wrong!), I was hoping someone
could verify and look at these numbers to see if the coil really will
perform before I spend all this time, effort and money.

If anyone is willing, here are the specs I came up with:

NST = 12,000v, 30ma, 60hz
Secondary = #22 wire, 20" long, 4" diameter, 765 turns-at-97%
Primary = flat spiral, I.D. = 6", 15 turns, .25" pipe, .25" spacing,
width=7.25"
Capacitor = .007uf
Toroid = Dmin= 4", Dmaj= 24"

The spreadsheet says secondary res F = 257kh, primary res F = 221khz.

My concern is if I use any larger cap, I can't get the prim/sec parameters
to match good enough. Also, I don't have any material for a toroid here
that I can look at so I assume 4" almunin flex hose but I don't know if 24"
is realistic. Lastly, the primary requires 53' of copper tubing. I am not
sure where to buy such a long length. I have seen only 25' at Home Depot.

Thanks.
    JC