Re: TC discharge... safe or not

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Brian by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ka1bbg-at-webryders-dot-net>

I agree,We tend to forget however, a TC output goes where it wants, and if
it power arcs to the primary side,,then to you,,POOF your gone. those odds
arent very good! be safe=dont! cul brian f.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, December 07, 2002 12:40 PM
Subject: Re: TC discharge... safe or not


 > Original poster: "Bert Hickman by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<bert.hickman-at-aquila-dot-net>
 >
 > All,
 >
 > OK... some numbers coming up.
 >
 > The resistivity of human flesh varies depending upon the type of tissue,
 > ranging from about 150 ohm-cm (blood) to about 2500 ohm-cm (fat). The
 > surface resistivity of dry skin can be considerably higher.  An average of
 > about 400 ohm-cm is typically used for estimating bulk resistivity for
 > humans. For comparison seawater, being "saltier" and a better ionic
 > conductor, has a resistivity of about 25 ohm-cm. For comparison, annealed
 > copper runs about 1.7 microohm-cm, making copper over 200 million times
 > more conductive than an average human being. Humans make fairly good water
 > resistors but lousy conductors unless we get overloaded and begin carbon
 > tracking...  =:^(
 >
 > The "skin depth" of a conductor is defined as the point at which the
 > current flow declines to 1/e, or about 37% of the total current. Skin
depth
 > is a function of a material's electrical conductivity (the reciprocal of
 > its resistivity), it's magnetic permeability, and applied frequency. It
can
 > be estimated using the following equation:
 >
 >     Skin Depth = 1/(SQRT(Pi*F*Mu*Conductivity))
 >
 > Plugging in the numbers for some common materials at 100 kHz and
converting
 > to english measurements:
 >
 >   Pure iron         =  0.26 mils
 >   Cold Rolled Steel =  1.48 mils
 >   Copper            =  8.23 mils
 >   Tungsten          = 14.71 mils
 >   Carbon            = 62.66 mils
 >   Sea water         = 31.33 INCHES
 >   Human Flesh (ave) = 10.44 FEET(!)
 >
 > The above table sheds some light on why you wouldn't want to wind a
 > resonator or primary using a steel conductor. More importantly, it also
 > shows that (at Tesla Coil frequencies) skin effect is virtually
 > _nonexistent_ for human beings unless you happen to be large enough to
 > merit your own zip code! RF current from a Tesla Coil will pass THROUGH
 > your most conductive tissues and organs: blood, nerves, and muscles and
 > will certainly NOT stay on your skin. In fact, RF current pokes holes
 > through your more resistive skin and fat layers (often cauterizing and
 > carbonizing them in the process) to get to your juicier, more conductive,
 > interior. RF burns can be quite painful and they take a very long time to
heal.
 >
 > So, what are the medical risks of passing RF currents from Tesla Coils
 > through your body?? We don't really know! There's anecdotal evidence that
 > at least temporary tissue damage has occurred in folks who have passed
 > larger currents (especially from CW systems). In high school I experienced
 > joint pains several hours after drawing multi-ampere currents from a VTTC
 > (lighting multiple 100W light bulbs). I've never had any symptoms from
 > small disruptive coils. I know of at least three other coilers who have
 > reported similar joint pain from CW coils.
 >
 > While short duration or low power levels are _probably_ safe (or at least
 > safer), we really don't know for sure. Play safely - you'll need to make
 > your own decisions on safety and risks.
 >
 > Best regards,
 >
 >msnip