Request for coil data. (fwd)

---------- Forwarded message ----------
Date: Wed, 15 Jul 1998 00:18:04 -0600
From: terryf-at-verinet-dot-com
To: tesla-at-pupman-dot-com
Subject: Request for coil data.

Hi All,

	I would like to request some information to help see what kinds of coils
produce what kinds of arcs and how that may relate to the thread about
output loading and such.  I suspect, in general, coils with a high
SQRT(Ls/Cs) ratio produce longer cooler sparks while coils with a low ratio
produce short but hot arcs.  With some basic data from a number of coils we
may be able to find a trend which will help in the design of new coils.
Anyone who would like to supply the following information can E-mail it to
me at:


This will keep this list from getting clogged up with a bunch of E-mails.
In a few days I will look at the data and report back to this list if I see
any great trends or whatever.  I will also compile the results and pass them
all along for others to see.  The data I think is important is as follows:
(Please include the measurement units such as inches, cm, picofarads, etc.)

Secondary Inductance

Length and diameter of secondary

Wire size and number of turns

Secondary Capacitance (this is combined terminal and self capacitance)

Coupling Coefficient from primary to secondary if you know it

Primary Inductance

Primary Capacitance

Spark Gap Type

Type of Top Terminal (size, smoothness and construction)

Primary Voltage 

Power Source (neon, pig, etc.)

Output Arc Distance

Output Arc "Character"  (White hot, thin purple, single streamer, many

Any other information you feel is important...

Please say if you are unsure of a parameter so I won't spend a bunch of time
trying to resolve a number that may be inaccurate.  If you don't know some
information, pass along what you have.  I can usually guess when needed.  I
am interested in only the standard spark gap type coils at this time.

I am especially interested at coils at the extremes.  Those that have
unusually long arcs and are great performers and also those that have
unusually short arcs.  If you have a coil that should perform well but
doesn't please pass along the information on that coil as well.  It is just
as important to look at poor performing coils and those that show unusual
performance characteristics.  Of special interest would be coils that give
great (or terrible sparks) in comparison to other coils for the same input
power.  Perhaps we can also determine why some coils have problems that
really should work.

If the Ls/Cs ratio is affecting the performance of our coils, perhaps this
information can help us find the best values to use.

Thanks very much for any help anyone may provide.  Hopefully, I can sort
through the responses ASAP.  I will pass along all the data in some
reasonable form so that it is available to everyone. 

Thanks very much.

Send info to:


Late Breaking News!!!
        I wrote this up at work.  I thought it was so neat, I left work a
little early to go home and send it out right away.  Unfortunately, on the
way home, I planted the front end of my car into the rear end of the car in
from of me.  My Cadillac will need the usual minor (but not cheap) bolt-on
"collision-expendable" plastic parts replaced.  The little Sunbird I hit
will now be playing in the accordion section of the local junkyard.
Fortunately, no injuries or anything bad except to my wallet. :-(((   Court
date, August 24......   Hey, is this dedication or what!!

BTW: I recently replaced my old 500cid 7000 lb caddy with a newer 4500 lb
version..... it still kicks butt!! ;-))

        Terry Fritz