Saturday, June 15, 2013

VAN DE GRAAFF generator

After completing the Wimshurst machine I decided to build a Van de Graaff static generator. I wanted to build one anyway.
First order of business was to gather some materials. A couple stainless steel bowls from K-Mart, a piece of PVC conduit from Lowe's, an old sewing machine motor, etc.
The construction was reasonably simple. It is simply a belt that runs on pulleys, one at the top and one at the bottom, and then there are brushes quite similar to the ones that I made for the Wimshurst machine at each end to pick off the static. The two bowls were fastened together to form a reasonably close approximation of a sphere which serves as a collector of electrons at the top.
Most instructions specify using a gum rubber belt, but one claimed vinyl coated polyester worked better so that is what I used. Shown here being super glued into an endless belt.
 Here it is finished setting on the work bench ready for testing. The wand with the door knob on the end is for discharging the static, but it turns out that using my hand is easier. Besides it really impresses people when I take a 3" or 4" spark without flinching.
And finally set up in the display room for demonstration. It will certainly generate static producing real long sparks, occasionally some nearly a foot. Interestingly they are almost painless when they strike your skin. One time I got zapped right on the end of the nose as I reached over to shut it off. I've had varying degrees of success getting it to make people's hair stand on end.
BUT it does a real job on a large Blond Barbie Doll head. She gets a real charge out of demonstrating it!