From: Bert Hickman
Date: Sun, 12 May 2002 22:51:24 -0500
Subject: Re: [TSSP] racing arc thought
Bart and all,
I agree with you re: static build up for grounded resonators being
mostly a phenomenon of the outer coating. If there were stranded charges
trapped on the coil former itself (a possibility with an excellent
insulators such as PVC), the grounded secondary winding should shield
most of the internal charge trapped on the former from appearing outside
except past the ends of the winding where the former is uncovered.
However, this would not be the case for a highly insulating outer
conformal coating.
My 10" coil uses a relatively thick (1/16" to 3/32") coating of Behr
Build 50 (which I think is a two-part clear epoxy resin) on a 10" PVC
former. The coating build up a very substantial (read "painful!")
charge, particularly near the top of the resonator. I can easily feel
the strong E-field with the hairs on the back of my hand, and hear the
snapping of partial discharges as they spark to my fingertips as I
approach and touch the highly charged regions of the conformal coating.
And, if I'm wearing rubber soled shoes, my entire body gets charged up
in the process - I can get zapped quite nicely by then touching the
grounded toroid. The first time this happened it was with my forehead...
OUCH! The charging/discharging sequence can be repeated many times
before the charge is finally reduced.
All bets are off when the secondary ground is removed... stranded
internal former charges may then contribute to coilers getting nailed
even more strongly while carrying loose formers. BTW, getting "nailed"
from a charged resonator is an official rite of passage for novice
coilers to graduate to "experienced" coilers... :^)
Best regards,
-- Bert --
--
Bert Hickman
Stoneridge Engineering
Coins Shrunk Electromagnetically!
http://www.teslamania.com
"Barton B. Anderson" wrote:
>
> Hi Marc,
>
> For coils which do contain a charge, I have to believe it's either in the
> former or coating. It may be the makeup of the poly. I use marine spar
> varnish and never get a static build up. From all the posts on the list
> regarding this subject, I've often wondered if it was the former. Before
> this last coil, I used sonotube. This last coil I used pvc. In both formers,
> a static charge still is not detectible (at least without a sensitive static
> meter). Because of this, I would suspect it is the coating itself. Materials
> such as nylon will remember and build a charge easily. It's possible some of
> the coatings others are using contain similar property's. This might explain
> why I haven't experienced a static charged secondary. The reason I chose
> marine spar varnish was due to running in freezing temps in MN (I wanted a
> flexible coating that wouldn't crack under extreme weather changes).
> Although I'm in CA now, I still use it.
>
> Take care,
> Bart
>
> marc metlicka wrote:
>
> > hello all,
> > I have some thoughts in the back of my mind about those thick poly
> > coatings over the windings on most coils, you see, I never saw a acing
> > arc until the very first coil that i coated with many layers of spray
> > polyurethane? Most all my coils are a "moto finish" red, this is because
> > i tended to coat the windings in layer after layer of insulating
> > varnish. I liked the 2kv per mil. of dielectric property and the color
> > is nice too.
> >
> > I did wind a very small coil onto a "creamora" bottle (polystyrene" i
> > believe) This coil would race up down and sideways even with a 530 nst
> > turned low. This was also the first coil that gave me the "extended
> > charge" zap after a run, since i coated it in moto finish, I tend to
> > believe the charge was in the former? I have a "gut" feeling that those
> > thick coats of poly can build a static charge that at the very least,
> > cannot help guard against racing arcs.
> > Just a thought of mine that i'd be interested in hearing other opinions
> > on.
> > Take care,
> > Marc
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.