Re: A photographic tutorial of Pancake Coil winding...with movies...(fwd)

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---------- Forwarded message ----------
Date: Fri, 22 Jun 2007 21:27:34 +0000
From: Jeff Behary <jeff_behary@xxxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: A photographic tutorial of Pancake Coil winding...with
    movies...(fwd)

Bart,

I kind of favour your explanation of this, because I've seen it happen 
before.  After adding the tall helix to my [now] Pancake Magnifier:
http://www.electrotherapymuseum.com/Forgotten_Tesla_Technologies/Magnifier_Pancake_System/index.htm
...and getting 4 foot sparks I started to try and add them to all Pancakes 
to see what happens.

In the cases where they weren't "friendly" I got more or less exactly as you 
said:  The helix would act simply as a top load for the Pancake, a spark 
obtained from the lowest portion to the highest portion or anywhere in the 
middle more or less looked the same.

Occasionally though I have seen dramatic increases in the spark length, with 
similar sized Pancake Coils and scenarios (16 - 18" pancakes of 18-20 AWG 
wire; 2-3 T primary of coarse wire; tall helix of fine wire) ...

Kind of similar in nature and topic was a Pancake invented by Ralph Browne 
of Salem Mass in 1906.  This coil gave a 10" spark from a simple kicking 
coil circuit.
http://www.electrotherapymuseum.com/_PatentLibrary/_BrowneCoil/index.htm

This pancake represents the exact opposite method of construction as to the 
famous coil from the Curtis book "High Frequency Apparatus".  In Ralph's 
coil the Pancake is multilayered, with the outside of the coil a flat spiral 
and as you move inward the number turns per layer increases more and more 
until you have a cylinder at the center post.

For years I looked at this patent and thought it a bad configuration.  Now 
as I have experimented with overloading the coils until they fail and seeing 
where they fail, it seems like an excellent design.  Where the turns of the 
secondary have the most resistance add the most insulation and in the middle 
where the voltage is highest and there is least resisitance place the most 
amount of turns.  Maybe I'll wind one on the weekend and we can see what 
happens.  I think it may be a really successful project.  In any case it 
should be done, Ralph didn't get much credit for that invention - it didn't 
go far in the medical field because of competition, though it did end up in 
a LE Knott Apparatus Co. catalogue as a demonstration Tesla Coil in the 
early teens...

Jeff Behary, c/o
The Turn Of The Century Electrotherapy Museum
http://www.electrotherapymuseum.com

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