Date: Tue Feb 13 16:05:03 2007

Author: Sam Sampere

Subject: NO SUBJECT

Post:
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I picked up a Science First Van de Graaff generator over the summer for
loan to HS teachers. I've used it a couple times and have been pretty
disappointed in it. I should have realized that when the front panel
reads "Van de Graff". The correct spelling is Graaff.=20

=20

I also heard what sounded like arcing coming from inside the base. When
I opened it up and turned it on and looked, I could see arcs from one of
the fuse connectors to the other. Hmmm. Why would the fuse be arcing to
itself??

=20

Why is the charging current so small - barely noticeable on a 100 micro
amp meter. Turns out that the motor ground isn't connected to the
chassis. Oh, the chassis is floating! So the supplied ground terminals
aren't really ground at all because they're not connected.=20

=20

A simple alligator clip connecting building ground to the base solved
all the problems. 25ish microamps, no arcing at the fuse, no shock
turning off the VdG, etc. Geesh!

=20

As far as small VdGs go, I think I like the Winsco best. Unless you have
an old Cenco unit. Those are great, especially when you make new pulleys
out of gray PVC and acrylic as Cliff suggested eons ago.

=20

Sam

=20

--------------------------=20
Sam Sampere=20
Syracuse University=20
Department of Physics=20
201 Physics Building=20
Syracuse, NY 13244=20
315-443-5999=20
315-443-9103 (fax)=20

=20


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I picked up a Science First Van de Graaff generator =
over the
summer for loan to HS teachers. I’ve used it a couple times and =
have been
pretty disappointed in it. I should have realized that when the front =
panel
reads “Van de Graff”. The correct spelling is Graaff. =




I also heard what sounded like arcing coming from =
inside the
base. When I opened it up and turned it on and looked, I could see arcs =
from
one of the fuse connectors to the other. Hmmm. Why would the fuse be =
arcing to
itself??



Why is the charging current so small – barely =
noticeable
on a 100 micro amp meter. Turns out that the motor ground isn’t =
connected
to the chassis. Oh, the chassis is floating! So the supplied ground =
terminals
aren’t really ground at all because they’re not connected. =




A simple alligator clip connecting building ground to =
the
base solved all the problems. 25ish microamps, no arcing at the fuse, no =
shock
turning off the VdG, etc. Geesh!



As far as small VdGs go, I think I like the Winsco =
best.
Unless you have an old Cenco unit. Those are great, especially when you =
make
new pulleys out of gray PVC and acrylic as Cliff suggested eons =
ago.



Sam



--------------------------
Sam Sampere
Syracuse University
Department of Physics
201 Physics Building
Syracuse,
NY 13244
315-443-5999
315-443-9103 (fax)









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