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Re: Oddball Oudin Coil (fwd)





---------- Forwarded message ----------
Date: Mon, 30 Mar 1998 15:03:40 +0500
From: "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Cc: ghunter-at-mail.enterprise-dot-net
Subject: Re: Oddball Oudin Coil

On Thursday, March 12, 1998 3:21 PM Gregory R. Hunter
[SMTP:ghunter-at-mail.enterprise-dot-net] wrote;

> Coiler Types,
>
> Many years ago, I read an article in an old hardcover book published
> by Scientific American Magazine.  The author described building a
> kicker-type coil, which he called an Oudin coil, using a Model-T
> ignition coil.  He removed the secondary coil, but left it intact.
> He rewound the iron core with lots of magnet wire, and retained the
> interrupter assembly.  This was the "kicker" coil. Next, he
> re-potted the old secondary winding inside a plastic sleeve and wound
> the outside of the sleeve with 5 turns of copper tube.  I can't
> remember what he used for a capacitor.  With the kicker coil
> interrupter buzzing, the repotted secondary (now air-cored) put out
> about 75KV.  Very interesting gadget. He used it to drive a homebrew
> X-Ray tube.  I wonder why the multi-layer secondary coil didn't flash
> over to itself?  If this physics hacker is still alive, he should
> join this list--he'd fit right in.

Hi Greg, sorry for getting in on this rather late but I've been occupied
over the last several days dealing with my migraines. First, the book you
mentioned is "The Scientific American Book of Projects for the Amateur
Scientist", by C.L. Stong. This book was like a best of from the Amateur
Scientist column that Stong ran in Scientific American until he died.
That book was an inspiration to most of us on this list! I noticed several
people responded to your post, some with partially correct answers. I will
try and clarify, the "kicker coil" is just an inductance and works on the
principle that the counter E.M.F. developed across an inductance is
proportional to the rapidity with which the current is broken. The kicker
coil is just the source of high voltage like a neon sign transformer is
used today. The vibrator of the kicker coil serves a dual function of
breaking the current to the inductor and acting as a spark gap for the
Tesla coil. The Tesla coil is comprised of the re-potted secondary winding
along with the 5 turns of copper tubing. If the coil was called an Oudin
coil then it was wired like an auto transformer, even though Tesla used
this configuration also it is called an Oudin coil in some circles. I
personally am rather impressed with the idea of using "kicker coils" to
power Tesla coils and have mentioned them several times on this list. I
think "kicker coils are viable alternatives to oil burner ignition coils,
neon sign transformers, and even pole pigs, especially in areas where the
normal sources of high voltage are either prohibitively expensive or down
right impossible to get. With the neon sign transformer being rapidly
replaced by low current solid state supplies, kicker coils may be the only
alternative for low to medium powered Tesla coils in the near future. For
your edification below is an ASCII drawing and a description of the
operating principle of a handheld Tesla coil used for vacuum testing
(identical to the old "violet-ray" coils) utilizing a "kicker coil" as the
high voltage supply. BTW the arrangement of the primary and secondary is
that which is usual referred to as an Oudin coil.

                                     ___
                                    (___)
                                      )
                                      )
                                      )
                                      )
                                      ) S
                                      )
                    __________________)
                 VG ____  _|_         )
                      | | ___C        )P
                     #( |__|__________)
                   C #(    |
                   O #(    |
                   I #(    |
                   L #(    |
                      |    |
                       115V
                     AC or DC

You have an iron core coil connected at one side of it's windings to
the line. The other side of the coil connects to a vibrating armature
almost identical to those found on the old induction coils. The
stationary contact of the interrupter is connected to the Tesla coil
primary P, the other side of the primary is connected to the Tesla
coil secondary S. the primary also connects to the moving contact of
the interrupter and the capacitor C is across the vibrating spark gap
VG. There should be an adjusting screw that pushes the moving
armature of the vibrating spark gap closer to or further away from
the stationary contact. Instructions for building several different
size Tesla coils driven by "kicking coils" are described in
Thomas Stanley Curtis's "High Frequency Apparatus" 1916 in chapter VIII
"Kicking Coil Apparatus", this book was reprinted by Lindsay Publications 
in 1988 and if you wish to order a copy, Lindsay's address is;

     Lindsay Publications Inc.
     P.O. Box 12
     Bradley, IL. 60915

     Tel: 815-935-5353
     Fax: 815-935-5477

The have a WEB site too but I can't remember their URL. BTW they have two 
catalogs, one on electrical or technical subjects and another on machining.
The electrical catalog has numerous books on Tesla, Tesla coils, and other 
High voltage devices like Van De Graff generators, Whimshurst machines, and
Induction coils.

                                       Sincerely

                                        \\\|///
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                                   Alfred A. Skrocki
                               Alfred.Skrocki.Sr-at-JUNO-dot-com
                           alfred.skrocki-at-cybernetworking-dot-com
                      Visit my Do-It-Yourself Aquarium WEB page at;
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