Date: Tue, 27 Mar 2012 12:18:15

Author: --- Bill Norwood

Subject: Re: Nakamura Van De Graaff "Raijin" - Safety

Post:

How about:
1. Are we talking about the capacitance of the VdG sphere or the human?
2. Capacitance of the human doesn't matter, since he/she is essentially just a straight wire (as a tree is with lightning) to ground?
3. The voltage of a VdG can be 100 to 500 Kv, and it would be at that voltage at the time of its discharge to the human.
Bill

-----Original Message-----
From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On Behalf Of Sam Sampere
Sent: Tuesday, March 27, 2012 11:19 AM
To: 'tap-l@lists.ncsu.edu'
Subject: Re: [tap-l] Nakamura Van De Graaff "Raijin" - Safety

You can do a back of the envelope calculation.

C is about 10^-12 F. If V = 100,000 V, which it isn't when you attach a human, then you can calculate Q, (.1 microC). If you want to assume a delta t of 1 microsecond, you can calculate I. Using these numbers, I get 0.1 A.

You can check my numbers, though, I did this quickly.

Sam

--------------------------
Sam Sampere
Syracuse University
Department of Physics
201 Physics Building
Syracuse, NY 13244
315-443-5999
315-443-9103 (fax)

-----Original Message-----
From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On Behalf Of Bill Norwood
Sent: Monday, March 26, 2012 2:55 PM
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] Nakamura Van De Graaff "Raijin" - Safety

Hi Taplers,
-Is it correct that one can "draw" through body about 10 amps for about 1 millionth of a second from a VdG discharge?
Bill Norwood, U of MD at College Park

-----Original Message-----
From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On Behalf Of Jerry DiMarco
Sent: Monday, March 26, 2012 2:36 PM
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] Nakamura Van De Graaff "Raijin" - Safety

I wonder if this modification bypasses any safety features of that VDG, such as current limiting. The low current limit is one of the measures that keeps VDGs safe...

Jerry D

At 3/23/2012 02:08 AM, you wrote:
>......
>Ok, the SF VdG comes with a large dome, that's why I bought it in the
>first place. Look at the lower combs. They are floating! That is,
>insulated from the base with insulating washers! So, remove the washer
>and replace them with metal ones AND also attach a wire connecting the
>comb to ground.
>
>Why the extra wire? The base is painted.
>......
>
>Sam

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