In article , todd wrote:
"Robert Bonomi" wrote in message
...

Note: then there were they guys building the *big* (as in 8-foot-plus
tall)
Tesla coils. _Those_ things were dangerous! While admittedly not
'static'
machines, *anything* that can maintain and sustain an atmospheric arc (a
"Jacob's ladder") in excess of 4 _feet_ is deserving of some serious
respect.

Sounds like they had a nice little toy there. In a previous career, I
designed and tested high-voltage insulators. I tested using an AC set that
could generate 1000kV and create an arc over 15 feet long.

That jibes w/ my recollections -- vague memories say they were playing
with circa 250KV.

We also used an
impulse generator which simulated lightning and switching surges that could
go up to about 2500kV. All of that was very interesting.

If you want even more fun, do high *current* testing and run 20kA through
some hardware. Ka-boom!

Shall I mention the time I saw somebody swing a crane boom in to the
_feeder_ lines to an operating sub-station, and only about 500 ft away
from the sub-station. The _flame_ front was merely a couple of =hundred=
feet *wide*. It went away fairly quickly -- like a second or so -- but
there were also several 'booms' and small clouds of smoke from the station
itself -- apparently 'protective' disconnects when the three-phase feed
went *that* unbalanced.

I've heard _one_ louder noise than that -- a lightning strike on a telephone
pole about 50' outside our back door. I *saw* the glass patio-doors I
was sitting not 10' away from bulge (about 3 inches!!) from the pressure
wave.