Re: van de graaff tube (fwd)

[<sroys@xxxxxxxxxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 7 Dec 2004 23:46:30 -0600
From: Dr. Resonance <resonance@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: van de graaff tube (fwd)


Our large machine was also an external belt machine.  It works very well at
1,000,000 Volts!  We run the supports up the inside of the belts.

Someone had a question regarding the column support.  We used polypropylene
rods which outperforms PVC.  The PVC leaks real bad above 8 inch ID.  12
inch ID tubes refuse to work at all even when charged by a 10 inch wide
belt.  Been there, done that as they say.

My large "pill capsule" design will be supported by four 2"dia.
polypropylene rods set at slight angles (25 degrees) to push inward.

When I get the design all finished, Antonio, I will run it past you to see
how your computer program does at accurately predicting performance in a
large machine.

Happy Holidays,

Dr. Resonance

>
> > My idea of an ideal VDGRF would be as follows:
> >
> > Horizontal cylinder 6 - 8 ft long x 48 inch dia.  40 to 46 inch wide
belt
> > runs into this cylinder.  Hemisphere end caps welded on both ends and
sanded
> > perfectly smooth.  Supports would be 4 long pcs of 2 inch dia.
> > polypropylene.  Sphere support at 4 x sphere dia. from any other metal
> > objects, floor, or ceiling.
>
> How would you power the belt? Maybe batteries inside one of the
> terminals.
>
> > We finally switched our large ball (40 inch dia.) to polypropylene
supports
> > with external belt and it went from 1 inch sparks to 32 inch sparks
> > immediately.  Belt was 8 inches wide running at 2,000 RPM.  Any faster
and
> > it begins to sound like a machine gun.  1 spark every 1-2 seconds if
about
> > right.  1 spark/sec starts to scare people, especially small kids.
>
> I like VDGs with external belt. I found a big HV ceramic insulator that
> looks suitable as a central support, between the runs of the belt. I
> was not expecting it to have so good insulation, but a test showed that
> it is as good as PVC as insulator, if not better.
>
> Antonio Carlos M. de Queiroz
>
>
>
>