Date: Thu, 21 Feb 2002 08:12:42 -0500

Author: John Cockman

Subject: Re: VDG recommendation

Post:

I am very happy with our Winsco generator, which has a variable motor speed
and gives good sparks up to about 12" to a grounded sphere. I had our
machinist switch the pulleys on a second older generator (upper electrode
positive), and we can now get 20" sparks between them. It is also fun to
watch them play tether-ball with a wad of aluminum foil.

John


----- Original Message -----
From: "Sam Sampere"
To:
Sent: Wednesday, February 20, 2002 6:04 PM
Subject: Re: VDG recommendation


> I have one of the old Cenco (no longer in existence) VdGs that I use for
most
> demos too, i.e hair raising. It works great and I'm now in the process of
> making a new column. The original one is nearing the end of its useful
life.
>
> I ordered a replacement belt from Sargeant Welch last summer. The new
belt was
> crummy looking, had many voids in the rubber, and the edges were jagged.
It
> didn't even charge very well, so I threw it out and put the old belt back
on.
> SW refunded the money, but didn't do too much to inquire about my lack of
> satisfaction. The model they offer in their catalog is a little different
than
> the original Cenco model, and frankly, I'd be a little hesitant to buy it.
I
> would buy one of the original Cenco ones though.
>
> I had a Science First one and that worked fine. I loaned it to a high
school
> teacher and never got it back. Shame on me! Live and learn. If I
recall, you
> need to get a ground sphere; it's not permanently attached like the Cenco
> version is.
>
> Sam
>
> brian holton wrote:
>
> > I have been hesitant to chime in, but I have used the CENCO unit for
five
> > years now and it has seldomly let me down. It has on occasion, in NJ
the
> > weather can be very wet at times, but overall, I have been very pleased.
I
> > have run the unit for hours on end with kid shows and it just keeps on
> > taking the abuse. There have been times when it functioned poorly, but
> > outside, by a pool, on a damp day, well one might expect that! I've
even
> > seen Van de Graaff's Van de Graaff function poorly at Princeton a number
of
> > occasions! They have one of the originals you know.
> >
> > One question, we had some discussion a year or so ago about large domes.
> > What is or was the outcome of that for people that wanted to make their
own?
> >
> > Brian Holton
> >
> > -----Original Message-----
> > From: owner-tap-l@listproc.appstate.edu
> > [mailto:owner-tap-l@listproc.appstate.edu]On Behalf Of Jerry DiMarco
> > Sent: Wednesday, February 20, 2002 11:41 AM
> > To: tap-l@listproc.appstate.edu
> > Subject: Re: VDG recommendation
> >
> > Thanks for the suggestions. It will be hard to make a choice.
The
> > Pasco VDG has some nice features, but claims only 4" sparks. A 1999
> > brochure from Science First shows a 400kV unit that delivers 12"
> > sparks! When I went to their website I could find only a smaller 200kV
> > unit. Is the large one still available, and does it really spark 12"?
> >
> > Jerry
> >
> > At 2/20/2002 09:49 AM, you wrote:
> > >I was in error in mentioning that the Van de Graaf we bought in 2000
was
> > >manufactured by Winsco. It was manufactured by Science First.
> > >
> > >* * * * * * * *
> > >
> > >Mike McFarland
> > >Resources for Instructional Labs and Lectures
> >
> > <><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
> >
> > Jerry DiMarco
> > Manager of Lecture Demonstrations and Instructional Labs
> > Physics Department, Montana State University
> > Bozeman, Montana
> > ph: 406-994-6161
> > fax: 406-994-4452
> >
> > Our Motto: "We don't use anything the way it was meant to be used"
>
>

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