Re: Natural streamer :)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

Hi Ed,

The salad bowls are the somewhat shallower stainless ones that have a very 
protruding rim(not benificial in any way!!).  I started off with a roll of 
black HV rubber insulation tape, then added a roll of regular electrical 
tape.  This worked OK but the more layers of tape you add, and the more 
surface of the rim and around the rim, the better your sparks.  The best way 
to check the insulation it to watch in the dark, if little sparks shoot out 
of the tape, then add more as you wish.  My sphere can be adjusted to be 
about 18" tall to about 24" tall (above the base).  When at 18" it will arc 
down to the bolts that hold the base together, but at 24" i can pull some 
really long sparks, sometimes to about 24".  Also note that when i add an 
aditional 12" diameter SPHERE on top of the salad bowls, i can get about 20" 
sparks but really thick, and they HURT!  They are enough to make the muscle 
in my arm sore, and leave little welts on my skin that look like big 
mosquito bites.  I really had a lot of fun with that project, but its summer 
now and the VDG can only make a little 4" spark with all the humidity.  I 
should also note that i use an air ionizer unit at the base to charge it.  
IT works just fine without it but is more consistent with it.  Good luck if 
you ever get around to those modifications.

Steve Ward.


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Re: Natural streamer :)
>Date: Tue, 16 Jul 2002 11:04:50 -0600
>
>Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><evp-at-pacbell-dot-net>
>
>Tesla list wrote:
> >
> > Original poster: "Steven Ward by way of Terry Fritz 
><twftesla-at-qwest-dot-net>"
><srward16-at-hotmail-dot-com>
> >
> > >
> > >       When I run my "big" [18" sparks, but only 35 microamps 
>short-circuit
> > >current] VDG everything within several feet stars to show visible
> > >discharge.  If they sharp points are close there isn't much voltage
> > >rise.  If I approach it with my hand I'm liable to get zapped, but if I
> > >hold a pin in my hand [pointed toward the terminal, of course] and
> > >approach nothing much happens.  Same phenomenon.
> > >
> > >       "St. Elmo's fire" is another manifestation of the same sort of 
>thing.
> > >
> > >Ed
> >
> > Wait a sec!!  Your VDG can give 35uA but can only give an 18" spark??  I
> > tested my VDG to have only about 7uA and can give about 22-24" sparks.  
>My
> > sphere is a 14" oblate made from salad bowls with about 4 rolls of
> > electrical tape around the rim.  Works fairly well with only a 3" wide 
>belt.
> >   I wonder why your machine has so much power but no big sparks (well 
>big
> > but not huge).
> >
> > Steve Ward.
>
>	Simple.  The column is only 18" long!  Someone gave me a piece of grey
>PVC pipe and I used it as I got it.  Have been intending to extend it
>for over 30 years but never worked up the ambition.  The upper terminal
>is a pair of the big spun oblates which I got from Frank Lee about 40
>years ago.  The belt is about 1-1/2" wide and running at high enough
>speed to require lots of tension to keep it from flying off the
>pulleys.  "One of these days" I intend to build a bigger one with wider
>belt, but don't know where to get a decent upper terminal.
>
>	As for the salad bowls, are you using the newer ones made of
>stainless?  If so, how do you handle the rims?  I used to use the
>anodized aluminum ones which were easy to cut and shape, but haven't
>seen one for many years.
>
>Ed