RE: Strange shock

["Richard Barton" <richardbarton-at-caving5.freeserve.co.uk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Yes, I've had this too, from a pretty small secondary, around 16 inches
long.
If you switch everything off, and even disconnect the secondary completely,
then run your knuckles along the turns, you will get a tingle. At first i
did this
by accident, and put it down to imagination, but have tested this since and
it
really happens. I would have thought that any charge would leak away within
seconds of switching everything off. I know we have capacitance, so we are
told, between turns (exactly how, when they are one piece of wire eludes
me),
and between the coil and the air, but how this phenomenon can happen up to
a minute after taking the whole set up apart defeats me. Even my bottle caps
can be touched within seconds of disconnecting !
						Richard Barton.

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, July 08, 2000 1:22 AM
To: tesla-at-pupman-dot-com
Subject: Strange shock


Original poster: "Chris Brick" <cbrick-at-rebelbase-dot-com>

Hello coilers-

I had a strange experience on the 4th.  We ran our coil in Santa Cruz, CA
as fireworks since they are illegal there.  We had a nice crowd and cars
stopping for about an hour.  The coil ran great, at one point for almost 20
minutes straight with no detectable heat in the MMC and no spark length
degradation.  Good quality show with consistent 36" streamers to air from
our little 15/30 NST.  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.

Also, those of you that are interested in rewinding a large transformer for
Tesla use may find it worthwhile to become friends with a local commercial
electrician.  I was just offered a 150KVA 240/2400 transformer for
$150.00.  It seems once they punch the wiring holes, they can't return them
to the distributor and can only sell them back at around $1 per KVA.  I am
going to collect a few for the cores and build myself a nice sized
transformer.

Thanks,

Chris