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Re: HV shock modeling for Tesla coils
Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
Excellent document you found!! Dangers of electrical shock is
everywhere in todays world. This document you shared, well, I plan
to use at work to educate some of the field engineers. I recently
finished getting our products Listed and Registered. Quite an ordeal
and education for any engineer to go through this. I fought long and
hard to make our systems safe (240 VAC, 20A units). 3 years of
putting my foot down payed off! The system passed with flying colors
(Hi-Pot testing, High Currents on Ground, Temperatures, everything).
They did a very detailed measurement and testing. I was quite amazed
at the process. High current AC is something new for my field
engineers (their knowledge is mostly mechanical). This document will
help me educate them.
I understand the SISG concern. Your right. New coilers with little or
no HV experience (or even electrical experience) can easily head the
SISG route. I am a prime example. Although I was a degreed electronic
engineer, I had no high voltage education or experience when I
started coiling. I started with a pole pig (not the smartest route to
take)! Luckily, I educated myself here on the list and elsewhere. But
safety protocols (other than the obvious of not touching anything) I
was still very green.
The SISG situation is very similar with respect to the dangers. The
patent thing is expensive (as you know). I personally wouldn't go
that route unless the product could pay for the patent lawyers.
Disclaimers are very important and a document of safety protocols
specific to the SISG may be wise. Standard NEC safety for the
voltages and currents call out specific safety requirements. It would
be a good idea to start there for the safety "requirements" and
incorporate at least the basics into the design. This includes safety
ground tied to a conductive casing around the electronics, wire
sizes, high voltage/current wire bends and routing, fusing, etc..).
Those are some of the type of items to pay attention to.
Tesla list wrote:
Original poster: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
I recently pulled the PIRANHA SISG web site temporarily off-line
until I could improve the safety warnings and data. Since PIRANHA's
charging system can be "thrown together" very quickly, I am very
concerned that "anyone" could make a powerful (too powerful) system
without much "HV safety knowledge". With two old microwave ovens
and a screwdriver, I could put it together in about 1/2 hour... The
SISG gaps still serve an "entry barrier" for many, but that could
change very quickly as fully assembled boards become common...
In studying its safety and possible risks, I ran across this very
nice safety paper:
Page 4 has a simple human body model and a graph that "sort of
determines" what various shock levels will do to a person. Such
data is easy to simulate with a circuit simulator to find peak and
RMS currents that make be delivered to a person in contact with
various parts of a Tesla coil system. The "death vs. time" and
levels that cause "fibrillation" as opposed to "just stopping" the
heart are pretty well explained...
PIRANHA actually delivers far less power than I thought into various
human fault loads (still easily deadly) but the added load is small
on fuses and other conventional safety devices. The output arcs
still stop, but the circuit "happily" fries the person instead...
So I was wondering if the human model in Figure 1 has a more
accurate version for voltages in the 5,000 to 25,000 volt
range? Also, if there is a larger graph like than in Figure 2 that
would extend into the 20 amp range? The graph could be extrapolated
for 2 orders of magnitude, but that might not be very good.
Hopefully, I can fairly well "predict" the effect of touching
various parts of the system in an effort to convince people that
they really need to be "super safe" and fully enclose and insulate
the thing like "I did" in my design. I also must ponder the known deaths:
and what safety measures could be taken "today" to eliminate the
possibility of those specific accidents from recurring.
It would be nice if systems like PIRANHA were not only among the
easiest and most powerful Tesla coils, but also among the "safest"!!
There will be a "temptation" to "skip" the NST and low powered coils
by the "newbee" especially if systems like PIRANHA are "easier and
simpler" to make... I am not sure how to "empress" upon them the
extreme dangers of such high powered state of the art things... An
advanced high powered coil, but the simplest to make... It could be
a very "deadly" combination... Have to figure out how to "fix that" ;-)
All thoughts, public and private, welcome ;-))) I guess it is time
to push the safety warnings to "another level" now that we are
getting "too good" at this stuff ;-)
BTW - Interesting reading:
BBTW - I might have to "push" the "PIRANHA" trademark and patent
thing now... In today's world market, that is typically
worthless... But it does provide significant leverage in the case
of the "abuse" of the technology...