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Re: New Coil!

 * Originally By: Lazer-at-netcom-dot-com
 * Originally To: Richard Quick
 * Originally Re: Re: New Coil!
 * Original Area: UUCPE-Mail
 * Forwarded by : Blue Wave v2.12

From: Stan Harle <lazer-at-netcom-dot-com>
To: Richard Quick <richard.quick-at-slug-dot-org>
Date: Thu, 5 Oct 1995 22:26:25 -0700 (PDT)
Subject: Re: New Coil!


On Thu, 5 Oct 1995, Richard Quick wrote: 
> 
> > 1) How do you effectively cut PVC squarely? I managed, but it was > >
tedious and slow. > > Get a metal strip tape measure. Start with the
factory cut end. Measure > back, then mark all around the circumference.
Score the mark with a > light saw fitted with a metal cutting blade (hack
saw). Once the groove > is scored, cut with a rough cut saw of any 
type

        Damn. I was hoping there was some elegant trick that I hadn't 
thought of.  Most of my shop experience has been with either wood or 
metal, and never with tubing.
> 
> > 2) How do you get the primary into a flat spiral? Again, I seem to
> > have managed, but it was a royal pain.
> 
> This one is accomplished with pure time. It is not easy, and neither
> is coil building. Wait until you wrestle a 100 foot length of 1/2 or 
> 3/4 inch tubing into a 15 turn flat spiral. It takes not days... but
> weeks or even months before the conductor is "trained".

        After fighting with 3/8 inch for several days, and still not 
quite finished, but functional, I find this easy to believe. Again, I was 
hoping there was a method that I hadn't thought of.  Looking over my mail 
earlier, I saw that there was a process posted on this. I'll look it over.

        Now for the killer question: How'd you make the neat flat coil on your 
video? My guess was that you got it roughed in, then ran several drilled 
pieces of plexiglass along the windings to form the support.  My friend 
says that you drilled and split the PVC, then epoxied or hot glued. Who's 
right?

> > Initial test of the capacitors indicate that 3 liter coke bottles 
> > don't have very much dielectric strength. Wish I'd gotten pictures 
> > of the corona.
> 
> I could have (should have?) warned you about this. This material is
> much too thin. 

        I'm glad you didn't. (g) I've been learning lots, and this was 
one more step in the process.  Besides, I wouldn't have seen that neat 
display.  The coil is pretty much done now, with the exception of the 
capacitance.  I popped four of the coke bottles before I realized what 
was happening.  Apparently, the "plasma globe" display is the dielectric 
and electrolyte breaking down, at least partially. When the coil has had 
power applied for a while, One of the arcs either settles, a heat spot 
forms, or something along those lines, and the plastic (and cap) fails.

        I ended up taking my toroid off, and getting perhaps an inch of 
spark from the bare wire. This is probably just the turns ratio rise from 
what little energy is making it through the caps.  From the severity of 
the discharge inside the caps, most of the energy is being dissipated, 
not held, in them.

        Incidentally, my whole aim has been to sort of "slap together" a 
coil, if all this can be called that, and then upgrade components 
piecemeal.  The gap is presently just a few wide gap statics. This seems
 to be barely enough to work, as they seem to 
be quenching with three xfrmrs, but not with four.  What's a good 
method for placing the tubing in the static cylinder gaps? I can't seem 
to gauge the holes and thus far have ended up with sort of slots. 
My first problem was that the section of tubing that became my gap wasn't cut 
straight in the first place. The second is to get the pipe properly 
positioned. Then I'll complete the rest of the tube placement.
        If I understand the gap function properly though:

        > I should be able to get spark as long as the gap is firing and 
        quenching, at least minimally. 

        > The main reason for splitting the gap into many segments is to 
quench the gap, secondarily for cooling purposes. 

        > A sign that the static pipe type gaps are quenching is the spark 
moving freely in the gap.

        Are these correct?

        Also, I came up with a pretty decent toroid.  I bought about a 10 
inch wheelbarrow tire, and stuffed it with newspaper until it was stiff. 
Then I wrapped it carefully around the tube with duct tape. I then 
placed some thick cardboard into the center, then wrapped the whole 
assembly with Al plumber's tape. Came out pretty good, at a total expediture 
of about 25 bucks.

You need to look at "tupperware" like thicknesses in your dielectric... 
(was that a hint or what?).

        Thanks. If I use a large bucket and threaded rod, does the top of 
the container _have_ to be covered, or can it be open?
        BTW, what did you pay for your capacitors again?

Stan

-Duct tape is _not_ a good dielectric!
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