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Re: Arcs off the fingers and getting killed in the process...
Tesla List wrote:
>
> Original Poster: Yurtle Turtle <yurtle_t-at-yahoo-dot-com>
>
> This may be controversial but... perhaps you can make
> it a requirement of all sites listed on the ring to
> meet some minumum standard regarding a statement on
> safety (something my site currently lacks). To make it
> easier, they could simply add a link to the pupman
> safety FAQ. Just a thought. Let the flaming begin!
>
> =====
> Adam Minchey
> yurtle_t-at-yahoo-dot-com
> www.geocities-dot-com/yurtle_t/tesla
> __________________________________________________
> Do You Yahoo!?
> Talk to your friends online with Yahoo! Messenger.
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Adam and all,
No flaming. However, the Safety FAQ probably needs to be updated, since
the "Frequency" section that discusses skin effect is misleading, since
we now know that skin effect really doesn't apply to Tesla Coil currents
flowing through a human body.
For newer coilers, here's the "straight skinny" on skin effect...
The phenomena of "skin effect" that is so easily demonstrated in metal
conductors, is not really applicable due to the relatively poor
conductivity of your body, which internally is approximately that of sea
water. Sea water is about 100 million times poorer a conductor than
copper. If you plug in the numbers, you'll find that the skin effect for
currents flowing through your body at Tesla Coil frequencies is
virtually non-existent(!)- the skin depth is of the order of 31+ inches
at 100 kHz! Even at the much higher frequencies used in medical
diathermy (13 and 27 MHz), the penetration depth is still 2-3 inches!
The reason why you feel little if any shock is NOT because the current
isn't flowing _through_ your body... it's because your nerves aren't
responding to the high frequency current flow (sort of like not being
able to hear a high-frequency audio signal). This does NOT mean that
your nervous system and other internal tissues cannot be damaged or even
destroyed! It's possible to sustain significant internal tissue damage
and yet feel absolutely nothing (at least immediately). This can be a
significant problem when taking hits off a higher-power tube-powered CW
coil. You'll typically feel absolutely NOTHING at the time, save a bit
of thermal heating... your fingers, hand and even your arm arm may get
warm. Minutes or hours later, you may feel aches and pains in your
muscles and joints from internal tissue damage! It's your body's way of
telling you "Don't do that!" <:^]
Taking hits from a low-power disruptive coil can be done if you remember
to be very careful. The main (and quite serious!) risk here is a
primary:secondary flashover that could connect you to the very dangerous
primary circuit. That's why it's very important that you stand on a
well-insulated surface, and that no part of your body is within arcing
distance to any other conductive objects or people. You do NOT want to
be grounded!
Taking hits from a larger coil can be extremely dangerous, particularly
disruptive coils using large topload capacitance. These can pack a
potentially fatal wallop! We want all of our list members to come back
to learn and play another day! :^)
Good luck, and safe coilin' to you!
-- Bert --