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Re: Conical and Pancake Coil Arguments... (fwd)



---------- Forwarded message ----------
Date: Mon, 18 Jun 2007 17:43:17 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Conical and Pancake Coil Arguments... (fwd)

Hi Peter,

I too found Jeff's post of great interest. As I am building a large flat 
secondary using magnet wire (#18) and those same thoughts crossed my 
mind. I guess I'll see. But to the point, if the coil were immersed in 
oil, the cotton would not be necessary. Even bare wire would be fine. If 
the coil is in open air, then the cotton covered wire comments do pose a 
problem.

Take care,
Bart

Tesla list wrote:

>---------- Forwarded message ----------
>Date: Mon, 18 Jun 2007 20:52:55 +0800
>From: Peter Terren <pterren@xxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: Conical and Pancake Coil Arguments... (fwd)
>
>Your comments on pancake coils are of interest to me. I still have (in the 
>loungeroom for the last 2 years or so) the materials for a 20 layer pancake 
>coil to be immersed in oil.  What has been stopping me going further is the 
>concern about air voids as you say.  I can see the rationale for cotton 
>covered wire here but oil soaked cotton is not going to let air out easily 
>either so it may not be the complete answer.
>Peter 
>http://tesladownunder.com/Tesla_coils_intro.htm#Multilayer%20Tesla%20coil
>
>
>---------- Forwarded message ----------
>Date: Sun, 17 Jun 2007 23:26:16 +0000
>From: Jeff Behary <jeff_behary@xxxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: Conical and Pancake Coil Arguments...
>....
>Tesla stated in 1897 that he used quadruple cotton covered wire to insulate
>his Pancake Coils, and later used normal magnet wire wound with a required
>thickness of string to achieve the proper distances in his coils. Tesla Coil
>X-Ray pioneer T. B. Kinraide used silk-covered magnet wire that was covered
>EIGHT times in order to insulate his coils properly.
>
>Today we have rubber and PVC coated wire.  These work great for Cylindrical
>and Conical Tesla Coils,
>no argument there, but for Pancake Coils they are useless.  The original
>cotton and silk covering allows insulation to flow THROUGH the windings and
>saturate all interstices of the coil up to the wire itself.  When plastic
>covered wire is used (even under vacuum impregnation) small voids and air
>pockets result from the tension of turns next to each other.  Sections of
>the coil can become "vacuum-tight" as it were though still have air trapped
>within these voids found between turns.  The result is a coil that works
>really well for a split second and then pours out black smoke from within.
>
>......
>Jeff Behary, c/o
>The Turn Of The Century Electrotherapy Museum
>http://www.electrotherapymuseum.com
>
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