RE: How to rise the secondary? (fwd)
---------- Forwarded message ----------
Date: Tue, 14 Jul 1998 23:32:00 -0600
To: Tesla List <tesla-at-pupman-dot-com>
Subject: RE: How to rise the secondary? (fwd)
At 03:02 PM 7/14/98 -0600, you wrote:
>---------- Forwarded message ----------
>Date: Tue, 14 Jul 1998 19:59:43 +0000
>From: "John H. Couture" <couturejh-at-worldnet.att-dot-net>
>To: Tesla List <tesla-at-pupman-dot-com>
>Subject: RE: How to rise the secondary? (fwd)
>The JHCTES program gives recomended values as defaults for all the input
>parameters as any program should. However, the defaults can be varied by
>about +/- 15% and sometimes more and still give a workable coil provided the
>system is in tune. This is why it is so important that any TC program
>provide automatic tuning when changes are made.
> Why do I keep pushing the JHCTES program? It is not perfect and someday a
>coiler will produce a better program. I am hopefully waiting for that day so
>I can see what I missed (without having to do all that work!). How about it
>Terry Fritz? And there are others capable of doing all that work.
> John Couture
You just had to get me started on this didn't you :-)))
I use computer analysis very extensively in my work on Tesla coils.
Computers are the only way to solve the complex multi-order differential
equations that govern the operation of our coils. I feel the models now
available can reproduce almost all currents and voltage levels with very
good accuracy. Often, I have seen something "strange" on a scope and have
gone back and looked on the model and there it is. The output sparks are
still rather mysterious but they are yielding their secrets fast and we
should soon have fairly good models for at least their average behavior.
I think there are three general categories of Tesla coil design
programs. The first, and simplest, are the programs that figure coil
inductances, resonances, and other very basic information from known
equations. The second, are programs like yours that try to predict the not
so basic but very important parameter based on test data and give a much
broader view of TC operation. The third are the standard electrical
engineering programs that are used for Tesla coil analysis. All of these
categories have their advantages and disadvantages. The simple calculator
programs give good numbers but lack any big picture information. The JCHTES
type programs can give an estimate of much more complex parameters and give
a better big picture view of TC operation but they sometimes are not able to
predict subtle parameters or allow for very precise estimations. The
full-blown engineering programs can predict behaviors to very good accuracy
and give great big picture views but are beyond the casual user's price
range and skill level.
The way I see it, is this. The complex high level programs can find
information and trends or do detailed analysis of data that is far too
esoteric for the casual user. These programs can also easily be adapted to
any situation very easily (even tube coils and magnifiers). The information
and knowledge the high level programs generate, can be used for the mid
level programs. The mid level programs may not be very adaptable but they
are focused on much more real world needs of coilers and are much easier to
use. The basic programs can either do the simple calculations or focus on a
difficult specific problem (such as coupling coefficients). All these
programs have their place and are needed. The only real requirement is that
they should all agree with each other and the basic theories or data should
be sound. Above all, if a program predicts something, it had better agree
with the real measured results.
Now that we are getting very good at measuring actual TC data we are
finding that some equations are good and some are having problems. The
equation Vo=SQRT(Cp/Cs)Vi is turning out to be a real winner. The equation
for wire length L=c/(4Fo) is a real looser. I feel both computer analysis
and real data are important in inseparable. The real data keeps the
computer models on the right track and the computer models can analyze
situations and data that we could never test just by building and trying.
Much of the recent stuff I have done is based on running many
computer models and noticing trends that are common to certain situations.
If I take a sample situation and go measure it in real life the results
match. I could never test and find these trends manually. The computer can
accelerate the discovery process thousands of times! Also the models
themselves are not abstract. They use actual parameters that one can go and
measure. Many models have proven to be simply wrong. But others have
worked perfectly. I often wonder why we didn't see it sooner because it was
so simple and obvious. Often it was because it didn't agree with some
theory that was faulty (like that 1/4 wave stuff :-)).
We truly are at a renaissance of Tesla coil knowledge. The
internet, computers, digital scopes and other factors have all come together
and allowed tremendous leaps in the state of the art. For so long, a faulty
theory would persist because no one could disprove it and it was the only
theory we had. Now if we have a theory we can probe and analyze it. We can
quickly judge its validity. If it's wrong, we trash it. If it is right, we
carve it into our desktop (the wooden kind). No more spending 50 years
wondering if it is right, despite the fact it never works :-)
So, do we need another program? Yes! We always need another
program because good ones are so few. However, they have a much higher
standard to meet today. If, for example, the output voltage predicted by a
program is higher than SQRT(Cp/Cs)Vi it will get attacked viciously. We
will calculate, theorize, and measure it into oblivion within days. If the
program seems to take primary to secondary clearance lightly :-))) we will
all question its usefulness. Malcolm and I discussed the results reported
by a certain pair of bothers from Ohio earlier this year and had a difficult
time figuring out they were wrong. Now it would take minutes to see the
basic errors. We are getting very good at this Tesla coil stuff and
everyone, from the most advanced to the beginner, is getting very
sophisticated. Today a number of people, the "newbies", mentioned that they
didn't understand the first notch. A few years ago "newbies" wouldn't have
understood what a capacitor was let along some subtle energy transfer point.
We still may not understand arcs and gap quenching well enough to predict
their behavior in advance of building them, but think about it... What else
don't we know?
I have done much programming and I have wondered if I should make my
own TC program "offering". It would take too much time away from other work
right now so I have put it off. It is, however, steadily increasing on the
list of priorities.
After a long and bazaar day in Terry's life.