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HV shock modeling for Tesla coils



Original poster: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

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:

http://www.nclabor.com/osha/etta/indguide/ig18.pdf

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:

http://hot-streamer.com/TeslaCoils/Misc/Deaths.txt

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 ;-)

Cheers,

   Terry

BTW - Interesting reading:

http://www-training.llnl.gov/training/hc/HVResearch/Grounding.html

http://pad39a.com/gene/shock.html

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...