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Re: VanderGraaff safety (fwd)



Brian,

Low resistance to ground?? What do you think is the resistance of a chain of
humans connected directly to ground? Does the skin effect have any relation to
this problem? It is a current spike!

Sam


brian whatcott wrote:

Folks,
I am sorry to say that publicizing the name and location of a teacher
who admits to being associated with a possible heart transient incident
is likely to be bad for his financial health. This list I believe is now
publically accessible and so is subject to casual viewing by honored
members of the law profession.

The current path would have been shared by all his student daisy chain.
But some subjects are more susceptible than others.
It is better to ensure the current magnitude is limited in one of two ways:
1) Limit the maximal charge if the path to ground is rather low resistance
(as here)
or
2) Limit the discharge rate by ensuring the ground path is high resistance
at all accessible points.

Brian

At 07:56 1/5/99 -0800, you wrote:
Below is a forwarded message from a non-subscriber. I never considered
this situation. The person nearest the water faucet would receive the
strongest impulse, right?

---------- Forwarded message ----------
Date: Sat, 02 Jan 1999 17:41:28 -0500

To: billb@eskimo.com
Subject: VanderGraaff safety

I've read most of your data on the generator but I experienced a small
mishap during our gr9 science demo before xmas. I am a teacher and we
were demonstrating the electric charges around the hair of a brave
student. They all wanted to try it and they joined hands in a daisy
chain. Someone touched the water faucet and they all felt a jolt. One
student came up tyo me and said his heart felt funny. It was racing
like crazy and I thought it might be fibrillating. I called home etc.
and was very worried for him even after the heart rate went down after
5 minutes. Did I do something that may have affected his health?


brian whatcott <inet@intellisys.net>
Altus OK



--
Sam Sampere
Syracuse University
Department of Physics
Syracuse, NY 13244
315-443-5999