Date: Tue, 19 Feb 2002 12:58:26 -0500

Author: "Reid, John"

Subject: RE: VDG tuning advise

Post:

Our VDG is probably about 30 yrs old. I came here about 4 yrs ago and
it did not work that well. I took it apart several times, cleaned everything
I could think of. Even tried different belt. Even used the hair
dryer trick. The best sparks were a few inches and after several
minutes no sparks would be generated.

Last year I finally spent some quality time with it and after much troubleshooting
figure out that the belt was carrying charge as it should. I figured this out
by placing the uppe
r comb at different positions along the belt and seeing what
charge I could remove from the belt. I concluded that somethings was wrong
with the rollers. I know they need to be made of different materials and they
are... I guessed that over the years the surfaces of the two rollers have become
coated with the same "stuff", whatever it may be. To test this I took a foil wrapper
from a candy bar and taped it around the top roller and put it back together.
Instant fix. We now get consistant sparks
of 8-10 inches (and a bit more on a real
good day).

This fix is temporary as the foil wrapper breaks after a while. It's enought to get one or two through a demo shows. If all this is right then I need to properly
clean or re-cover the pulleys, but I haven't done that yet.

John

================================================================
John D. Reid, Ph.D. Geology & Physics Dept.
Assistant Professor of Physics Lock Haven University
(570) 893-2078, 227 Ulmer
Lock Haven, PA 17745
http://www.lhup.edu/~jreid
================================================================

-----Original Message-----
From: Paul Nord [mailto:Paul.Nord@valpo.edu]
Sent: Tuesday, February 19, 2002 10:30 AM
To: tap-l@listproc.appstate.edu
Subject: VDG tuning advise


Good Day,

I know that this is going to generate an absolutly huge number of
responses. And, if I'd been paying better attention before, I should know
all the answers. But, here goes.

Our Ce
nco VDG suddenly stopped working this spring. It's about 4 or 5
years old. I took it apart and put it back together a couple of times
yesterday. At one point I was getting 4 inch sparks. Then, I ran the
motor up to full speed. The belt seemed to make some noise. I think that
it was hitting itself somewhere in the middle of the collumn. After that,
I got nothing! No charge. Nada!

I do note a few oddities. It appears that there's a fine spray of oil
from the berrings. The oil is on the upp
er and lower ends of the tube.
We've got a few spots on the belt where the combs have worn into it. And
there's also a bit of a spray of shards from the belt around the lower end
of the tube.

Ok, so let me have it, what are your methods for tweeking a faulty VDG?

Thanks,
Paul

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