RE: Tesla Coil Computer Programs

["Ross Overstreet" <ross-o-at-mindspring-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

The spreadsheet tells you the primary resonant freq based on the chosen C
and chosen number of turns.  All you need to do is make the primary res freq
somewhere in the neighborhood of the secondary res freq.  Most people report
that the theoretical tuning point and the "best running" tuning point to off
a little.  My coil is happiest with a measured primary resonant freq about
3% lower than the measured secondary resonant freq.

It's important to keep any design tool flexible b/c you never know what an
individual is trying to do.  Many of us build a cool looking secondary with
some big arbitrary metal thing on top, scrounge up some capacitors, and want
to figure out about how many turns the primary would need.  Others can't
easily adjust the tap on the primary and want to figure out something about
topload or secondary size so that the system resonantes.

Most anyone that can operate a calculator could go through the 5 or so
essential equations and design a coil by hand in a matter of minutes.

Newbies:
The basics ideas in the various TC programs are straight foward

1.  Make sure the power supply can charge the cap to a voltage high enough
to jump the spark gap at least once every half cycle.

2.  Figure out the resonant freq of the secondary circuit.  You can change
this by changing the capacitance of the secondary (mostly from topload) or
the inductance of the secondary (geometry, number of turns, etc)

3.  Figure out the resonant freq of the primary circuit.  Again, you can
change this by changing the primary capacitance or the the inductance
(geometry and number of turns in the primary)

4.  Change something in either the primary circuit or the secondary circuit
so that the resonant freqs are about the same.

Through lots of iterations, people have found some best practices in coil
design that give the biggest arcs for the least time, money, and trouble.
These can be found by researching the 150+ Tesla web pages on the Tesla Coil
Webring.  This includes stuff like aspect ratio, number of turns, size of
wire, etc.

Cheers,
Ross-O

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, July 22, 2000 10:30 AM
To: tesla-at-pupman-dot-com
Subject: RE: Tesla Coil Computer Programs


Original poster: Megavolt121-at-aol-dot-com

John
 I'm a happy user of both Ross and Ed's spreadsheets. I would like to point
out that by listing all the different values of the primary at different
turns. This is a big advantage if i want to knwo where to start tapping a
primary when i'm testing out a coil for both the first time and w/
different top loads.
-Alan

Original poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net>


 Ed, Ross -

 I have used this spreadsheet and found it very useful as a TC calculator.
It
 is similar to the JHCTES Ver 3.1 program. However,  one thing I would like
 to point out is that with the JHCTES program the user enters the primary
 capacitor value and the computer finds the number of pri turns required to
 keep the system in tune. This avoids the user having to vary the turns
until
 the proper capacitor value appears.

 John Couture


 -------------------  snip

 I agree.  Whenever I run a set of calculations on someone's coil, I just
 save
 it under their name and can go back to it in the future.  I find the
 spreadsheet program very useful for finding out where to tune someone's
 primary by playing some what if type calculations.  I enter the secondary
 and
 toroid information.  Then the primary info and check the required capacitor
 value.  Then I go back to the primary calculations and slowly decrease or
 increase the number of turns, watching the calculated capacitor value until
 it gets close to the capacitor value that they are actually using.  Works
 for
 both of my coils.

 Ed Sonderman