Re: van de graaff tube (fwd)

[<sroys@xxxxxxxxxxxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 28 Nov 2004 23:18:21 -0600
From: Dr. Resonance <resonance@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: van de graaff tube (fwd)



Assuming you are spraying the lower pulley at 5-7 kV DC, the 2.5 inch wide
belt will deliver charge to the upper terminal at an approximate rate of
12-15 uA DC.  If you are using a self-excited design, the max charge rate
will be approx 3-4 uA DC.

A gray PVC tube will leak at approx 1 uA downward.  A black PVC tube will
leak at 2.5 uA DC downward, so the black will not work.  Your HV terminal
will not acquire a charge.

Use a gray tube, schedule 40 PVC, and apply 3 coats of red gylptal inside
and outside prior to using the tube.  Also, be sure to sand the tube inside
and outside prior to coating to remove any carbon particles (impurities)
that would cause additional downward leakage.

A 16 inch sphere will produce approx 450 kV at the top terminal.  Keep the
tube length to at least 40 inches long so surface tracking at this potential
will not become a problem.

Happy Holidays,

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913


>         i was given some tube from work which is 7/16" wall thickness so i
thought i haver rollers waiting and this is perfect for mounting the rollers
on. so my question is, this stuff is black pvc (i think) but worst case it
could be conductive! will this affect things? im guessing it wont as nothing
will be touching it but you never know. i know black pvc works fine as a
tesla coil former but this is a different beast. i will be aiming for 2.5"
wide belt and this stuff is 4" and i hope to have 16" sphere on top.
> any help much appreciated
> cheers
> colin heath
>
>
>