Re: Strange shock (fwd)

["Chip Atkinson" <chip-at-pupman-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Date: Mon, 10 Jul 2000 19:15:32 -0700
From: Ed Phillips <evp-at-pacbell-dot-net>
Reply-To: ed-at-alumni.caltech.edu
To: Tesla list <tesla-at-pupman-dot-com>
Subject: Re: Strange shock

Anyhow, after the show was over I proceeded to
> dismantle the coil as I have done a hundred times.  I removed the secondary
> after disconnecting all the wiring and capacitors.  I received a small
> shock from the secondary while holding it in my hands, away from everything
> and totally disconnected.  One of my engineer friends didn't believe me so
> he picked it up and got the same shock.  It is built on a 4". thin wall PVC
> drain pipe, sealed, and has 1/4x20 bolts epoxyed in each end.  The larger
> of the two shocks I got was from the bottom bolt.  The bottom of the
> winding is connected to the bottom bolt for grounding.  The top bolt is
> used to connect the toroid and doesn't have a connection to the
> windings.  Any thoughts on why there would be some charge built up in the
> secondary?  Either way, it didn't hurt and I didn't die, but I sure would
> like to know what it was all about.  I am not too familiar with Leyden
> Jars, but Steve the engineer had some ideas about the possible cause.

	Anyone who has fooled with a coil (at least one with some form of
varnish over the secondary) much  has observed similar effects. It is
clear that there is residual charge in the varnish, which in turn
implies that there must have been some rectification involved. 
Well-known phenomenon, explanations less well known.  I've gotten almost
painful shocks from a small 3" diameter coil coated with several layers
of shellac.

Ed