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Re: streamer hit
At 10:51 PM 11/11/98 -0600, you wrote:
>Tesla List wrote:
>snip>
>Terry and all,
>
>I've been reading the many interesting posts on this topic! Lots of
>rather exotic methods of estimating the current distributions. However,
>you can get a quick estimate of skin effect by using the operating
>frequency of a typical operating Tesla Coil by using the permeability
>and conductivity of sea water to model the EM inside of your body.
>
>The bottom line:
>===============
>At the relatively low operating frequencies used in Tesla Coils, there's
>virtually NO "skin effect" at work - the effective "skin depth" of your
>body is "deeper" than you are thick! For example, the RF current from a
>100 kHz system has a "skin depth" of about 31 inches inside your body.
>Unlike a good conductor, the current will NOT be confined only to the
>outer surface of you body.
>
>The fact that you may not "feel" the RF current (particularly from a CW
>coil) does NOT mean that it won't do any physical damage - your nerves
>are simply not responding to the RF current - sort of like being unable
>to hear a damaging level of ultrasonic sound. Any current flowing
>through your body (once it penetrates your skin), will be concentrated
>through the best conducting portions of your body - your nervous and
>circulatory systems. And make no mistake, excessive/prolonged current
>flow can result in temporary or long-term nerve or organ damage.
>
>Worse yet, if you happen to be grounded through an accidental flashover
>to some other part of your body (toes, elbows or kneecaps...), the
>discharge from a fully-charged topload and coil self-C is actually a
>direct current capacitor discharge through your body. Taking a "hit"
>from a multi-Joule coil will most definately "smart"... a hit from a
>larger system can kill! Ao, don't buy into the old skin effect folklore,
>guys - it ain't true!!
>
>And, SAFE coilin' to you!
>
>-- Bert --
>
>
Thanks Bert,
I had heard the skin effect stuff for so long I really didn't question it
till recently. I think you pretty much hit everything right on the head.
I never was a big fan of getting shocked or taking arcs. The fact that
these high frequency currents travel through ones guts and all is pretty
important to understand. Just like X-rays, we need to know as much about
our risks as possible. Large coils are pretty ominous when operating and
not too many people run TOWARD them :-)) Smaller coils don't have the
freight factor to keep us away and we need to be aware of what they are
doing to those of use who like to "play" with the arcs.
It would be interesting to know is anyone has noticed any long term
affects of arcs through the body aside from the obvious burns and the
mentioned short term tingling muscles?
Terry
References: