Date: Tue Mar 31 15:46:29 2009 Back to Contents ------------------------------------------------------------------------

Author: Bill Alexander

Subject: Re: VDG question

Post:

I bought one of the VDGs from Pasco, and it did not work very well at all, when first plugged in. Upon taking off the top, and the bottom, I found that both "combs" had gotten out of place in shipping (the bottom one is not very solidly held). After moving them close to the belt, it works great. Previously, with our old VDG, one time it just quit producing much of any spark. I took it into the optics dark room, and discovered a 1 mm or so sharp piece of metal that was the problem. Invisible out in the light, but in the dark the corona discharge was obvious.

Also, in my experience the best sparks are obtained from VDG to ungrounded sphere to sharp grounded wire about 6 inches on the opposite side of the ungrounded sphere. Nice sparks jump to the sphere, and also jump from the sphere to the point. I have a plastic meter stick with a sharp piece of welding rod on the end, with a long wire to ground.

Good luck,


Bill A.

----- Original Message -----
From: "Santos Ramirez"
To: tap-l@lists.ncsu.edu
Sent: Tuesday, March 31, 2009 11:51:55 AM GMT -08:00 US/Canada Pacific
Subject: [tap-l] VDG question


Tappers,

A professor here ordered a
Cenco Large Van De Graaff # CP33891-00
from Sargent-Welch last week (description follows).

Problem is - it does not generate very large sparks.

Has anyone else had problems with this VDG?
Is it fixable?

(We have 2 old (circa 1960) VDGs that work great and
the one ordered was the only one close in style to the old ones)

Santos
TAMU -Physics
***************************


Generates 400kV. 105k More than Any Other Van de Graaff!

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From tap-l-owner@lists.ncsu.edu Tue Mar 31 15:46:29 2009

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