Re: Measuring inside a coil

To: tesla-at-pupman-dot-com
Subject: Re: Measuring inside a coil
From: "John H. Couture" <COUTUREJH-at-worldnet.att-dot-net> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Sun, 11 Apr 1999 10:41:35 -0600
Approved: twf-at-verinet-dot-com

  Reinhard, All -

  I was not thinking of bringing wiring into the sphere from outside. The
wiring from the sensor inside the coil would run to inside the sphere and
instrumentation which would be energized by batteries. No outside wiring.
The sphere would have to be large enough to contain a person. The question is
would the wiring going from the inside of the coil to the sphere nullify the
protection of the sphere as a Faraday gage? It is assumed the secondary coil
insulation is adequate. Could an induced electric field from the coil and on
the instrument wiring be a hazard to a person in the sphere?

 Your question about the safety of someone inside the secondary coil is an
interesting one. This is not a Faraday gage so the conditions are obviously
different. In fact the conditions are similar to when linemen work on high
voltage lines that are energized. However, inside the coil the person would
be exposed to electric fields with large voltage differences and this
condition would exposed the person to very high risk. Not recommended. It
would be a challenge to map the electric and magnetic fields inside the
secondary coil.

  John Couture

-----------------------------------------

At 12:29 PM 4/8/99 -0600, you wrote:
>Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> 
>
>Hi John, all
>
>>Original Poster: "John H. Couture" <COUTUREJH-at-worldnet.att-dot-net>
>>
>>
>>  Brian, All -
>>
>>  Greg or someone was inside the secondary terminal not the secondary
>coil.
>>With a large TC the magnetic fields could be very high so don't wear
>your
>>wrist watch.
>>
>>  However, would it be possible to use a Hall effect magnetic field
>sensor
>>with instrumentation circuits terminating in the secondary terminal
>(toroid)
>>be a method to detect the fields? Would this nullify the Faraday shield
>>effect of the terminal that is protecting the person reading the
>>instruments? Are there any volunteers?
>
>While I don´t want to volunteer (and I wouldn´t fit inside
>my coil or toroid anyway :o)), I think as soon as you bring
>any kind of conductor inside a Faraday cage, all safety bets
>are off. I think you would nullify the effect of the cage. IF the
>cage is connected to ground, you should still be safe from
>outside strikes, but if any of the measurement cables that
>go inside the cage get hit, (I think) there would effectively
>be no cage present. Of course, you MIGHT be lucky and
>not get any strikes to the measuring cables INSIDE of a
>secondary, but I would be tooooo chicken to try. (:o)
>
>While I am sure that someone will point out the flaw,
>question: Wouldn´t the secondary itself be a sort
>of Faraday cage for someone standing inside? While
>I have seen interturn arcs, etc, I have never seen a
>coil arcing inside (from one side of the former to
>the other). Saying this, I am assuming NO conductors
>enter inside the secondary coil former, of course.
>
>Coiler greets from germany,
>Reinhard
>
>