New spark record

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

Original poster: "Jason Johnson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <hvjjohnson13-at-hotmail-dot-com>

Last night I ran my rebuilt 4 inch coil, preparing it for showing everyone
that'll be at my house tommorow for christmas celebrations. The basic coil is
unchanged electrically, but has a nice new primary and some mechanical
improvements over the last coil. Its been a while since I posted my coils specs
so here they are again:
 
power supply: two series MOTs for 4800 volts
capacitor: 110nf 18kvdc MMC
spark gap: airblast gap with two 1/4" brass threaded rods, 2cfm -at- 35 psi or so
primary: 7" i.d. 1/4" tube w/ 1/4" spacing cable tie design
secondary: 4 inch PVC wound for 23 3/4" w/ 28 guage magnet wire
topload: 4"x17" al dryer duct with 8"x23" al dryer duct sitting directly on top
 
Power input was from a 120 volt 15 amp circuit also with the air compreesor on
it. I ran it for around 30 min (not continuos) last night in the -5 degree
weather. Longest sparks (about five of them) of the night were at least 6 feet
long. They came off the toroid reached way out and then curved over touching
the ground. You could see where they hit in the snow on the ground. The
straight line distance was just over five and a half feet, but with all the
curvature I would estimate them at 6 to 6 and a half feet. This is very good
considering that my ground was nothing more than three chunks of steel channel
6' long laying on the snow. Also with the cold weather I could run longer
before the gap power arced and tripped the breaker. 
 
One thing about the coil that I didn't like was I was getting several racing
sparks while I was getting the sparks that touched the ground, until I put a
piece of steel on top of the coil to direct the sparks out and up. When they
were out like this I couldn't get them to stretch more than 4 and a half feet
or so but there were several branching sparks this size coming off each side of
the bar, but at least I didn't get any racing sparks this way.
 
MOTs rule
Jason Johnson