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

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---------- Forwarded message ----------
Date: Sat, 23 Jun 2007 17:41:08 -0700
From: Ed Phillips <evp@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: A photographic tutorial of Pancake Coil winding...with
    movies...(fwd)

Hey Dave & Bart,

I saw your interesting Pancake Coil and Cylinder setup.
There was mention of strong shocks obtained even minutes after powering 
down.  I have noticed this with all of my Pancakes.  I think it has 
something to do with the wax and rosin mixtures used in the coils, making a 
type of Electrophorous.  (I'm sure you have seen those in the old Static 
Electric Books).  Since you use acrylic, maybe this also has a similar 
effect?  There is a considerable static charge buiilt up in these apparatus. 
  I have even placed a cardboard cylinder on top of the Pancake Coils and 
obtained sparks from the top with a metal electrode of a Wimshurst Machine!  
The sparks weren't huge, 1/2" or so, but still it was a lot of fun."

	I think that just about anyone who has played with a coil much (at least one covered with some sort of varnish - I've never tried it without it) have observed similar effects.  I believe the "wisdom on the street" is that there is rectification because of the shape of the coil and the voltage gradient from it and that the result is charge stored in the insulating coating.  Often running ones hands up and down a coil which has been operating produces very noticeable jolts. The wax or acrylic would charge similarly I suspect.

Ed