From: Bert Hickman
Date: Sat, 14 Sep 2002 05:28:08 -0500
Subject: Re: [TSSP] Top Voltage
Hi Terry, Excellent work!! A couple of brief comments now (just leaving for a ham fest ~150 miles away)... The polarity reversal for larger diameter terminals is to be expected - long streamers should preferentially propagated when the HV terminal is positive with respect to ground. Although you can force leaders to propagate from a negative HV terminal (or a cloud, as in lightning), it takes considerably more voltage to propagate a negative leader than a positive one. The difference between the smaller and larger spikes may be the difference between streamer (or corona) bursts and actual leader formation/propagation. Streamer bursts are very fast, but "cold" discharges that are the precursor to the formation of a hotter conductive current channel (leader). The last jpeg of video frames shows the difference between the two discharge forms beautifully - look especially at the very last frame versus most of the others. The fainter discharges are very fast (10's of nanoseconds) streamer bursts - these should have ampere level currents. The hotter leaders (what most coilers mistakenly call streamers) are fed by larger impulses of current during propagation as well as displacement currents to/from the leader capacitance. You can also see the fan or streamers that feed the tips of the leaders in many of the shots. Great stuff!! What would be extremely valuable now would be "single shot" ringup events coincident with video of the same events so that we can begin to correlate the form(s) of the discharge with corresponding current distribution/amplitudes. This could be followed by multiple bangs to look at just how bang-to-bang propagation works. This is fantastic stuff, Terry! Best regards, -- Bert -- -- Bert Hickman Stoneridge Engineering "Electromagically" (TM) Shrunken Coins! http://www.teslamania.com "Terrell W. Fritz" wrote: > > Hi Again. > > I replaced the resistor in the sensor head with a 0.1 ohm. It did not change > things much except the levels. > > http://hot-streamer.com/temp/PaulArc/020913-1/Tek00000.gif > > So 1A = 2.44mV now. or 10mV = 4.1A > > The head now has an impedance of 0.1 ohms too which cleans things up a bit. We > still see a 4 amp spike and all but the ring down following it is more clear. > Probably something real there. > > Here is a backed off view of the thing: > > http://hot-streamer.com/temp/PaulArc/020913-1/Tek00001.gif > > One big spike and many little spikes. > > Here is a closer especially active burst: > > http://hot-streamer.com/temp/PaulArc/020913-1/Tek00002.gif > > I turned up the power (the meter froze so don't know the voltage. Probably > proportional to base current) the spikes started going UP!! > > http://hot-streamer.com/temp/PaulArc/020913-1/Tek00003.gif > > Firing on the first high voltage peak now which is opposite in polarity. > > http://hot-streamer.com/temp/PaulArc/020913-1/Tek00004.gif > > As I continued to turn it up, this spike just gets bigger and bigger. 100mV = > 41 amps!! > > http://hot-streamer.com/temp/PaulArc/020913-1/Tek00005.gif > > http://hot-streamer.com/temp/PaulArc/020913-1/Tek00006.gif > > So it appears these arcs are just single very short bursts of energy at this > level. I tired to get a nice picture but catching a 50nS event is really > really hard ;-)) Maybe I can get it on video... > > An hour later........ > > Ok, this is the best I could do at catching some of the higher power shots... > > http://hot-streamer.com/temp/PaulArc/020913-1/Image10.jpg > > Cheers, > > Terry
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.