Re: Mini VDG? (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 21 Mar 2004 09:39:45 -0500
From: David Speck <dave@xxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Mini VDG? (fwd)

Antonio,
That is a cute VDG, but not the one that I had.  Mine had a 3" round
plastic terminal with heavy nickel or chrome plating on it, a dark blue
cylindrical column with "corona rings" molded into it, and a maroon -
brown base which held the crank assembly.  I still remember getting
airplane cement on my fingers in the process of winding coarse wool yarn
around one of the pulleys.  The collector electrode was a simple strip
of brass that sat very close to the belt.

The weakness of the design was the 1:20 step up arrangement of the crank
action.  The crank knob was mounted on a flat 3" cylindrical disc with
gear teeth on the inside circumference.  IIRC, the plastic shaft on the
1/2" driven pinion gear wore through and broke fairly quickly, but not
before I was able to do some nice demonstrations for my grade school
classmates.  Aaaah, the good old days!
Dave

I have this VDG from a kit (from 30+ years ago):

>http://www.coe.ufrj.br/~acmq/vdgkit.jpg
>The belt (rubber band) and the charge collectors are missing.
>The crank was difficult to turn, and the sparks produced were small,
>but it worked. I still remember the shock that it gave me when I tried
>to charge an improvised Leyden jar with it.
>
>