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Re: Getting zapped by my unpowered Secondary
Original poster: "Charles Hobson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <charles.a.hobson-at-btinternet-dot-com>
Original poster: "Ray Robidoux by way of Terry Fritz <twftesla-at-uswest-dot-net>"
>Well first off when I grab the secondary, the power cord is UNPLUGGED so I
>know it is not from stray AC leakage. Secondly, when I say I wrapped it in
>Saran Wrap, I mean about 40 to 50 layers of Saran.
>Also one thing I did when I wound my coil was to apply 3 strips of double
>sided scotch tape to the form. I laid these out lengthwise on the form to
>help hold the wire in place as I wound the coil. This was a fantastic help
>in holding the wire, but I wonder if this tape may not be the dielectric
>that may be holding the charge that I am experiencing now. BTW my coil
>form is a thin cardboard tube 2.5" in OD, treated with Thompson's
>and shellac. The finished coil was then sprayed with polyurethane.
>The reason for my question is not to prevent pain to myself, BUT to
>what is going on. The secondary circuit is formed by the Ls of the coil an
>Cs of the self capacitance of the coil and topload combined. If I and some
>are getting zapped and still others are not. Then something in our
>methods are producing coils with larger and smaller Cs from person to
>Knowing what makes this difference and which differences are better than
>is what this question is all about.
>So perhaps the question needs to be changed slightly to ask, what
>methods produce zaps and which do not.
Your original question was OK. It led to some very interesting responses
regarding the dielectric materials used in construction of TC's, and to your
second question As I said before, I never experienced zaps as you did.
Anyway, I've built only two coils, one using a large polyethylene former,
and the other a high quality 3" by 15" cardboard former. The coils were
wound on these and subsequently sprayed with several coats of polyurethane.
I can't say this combination won't produce zaps because the climate where I
am at has been very damp.
I did get a very bad electrostatic discharge once, one I'll never forget. It
was due to a well known cause under the right conditions: high altitude,
very dry cool air, etc. Believe it or not, that happened inside the Antler
Hotel in Colorado Springs back in the winter of 1952. It was caused by
their thick carpeting. I entered the place, dragged my feet over to the
reception desk, set my suit cases down, continued dragging my feet to the
men's room. A nice blue 2 or 3" spark occurred there at a urinal with a
vengeance. ( I was wearing new thick rubber soled shoes)