Re: Static discharge from my air compressor

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

Original poster: "David Speck by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Dave-at-DavidSpeckMD-dot-org>

Along the same line,
a long time ago, back in the Chem labs at Cornell, I was passing a room
near twilight when I noticed a flash of light from inside.  I availed
myself use of my master key (I worked for the instrument shop as a
repair tech -- happiest days of my life!), and found a large glass
vacuum rack being kept under maintenance vacuum with a mechanical
roughing pump and a large, all glass mercury diffusion pump.  

For a while, I thought I was seeing things, but it turned out that about
every 45 seconds, there was a brief steel gray discharge down the bore
of the diffusion pump, much like a dim xenon strobe tube.  It turned out
that the mercury vapor in the pump was transferring charge between ends
of the pump, just like a Van deGraaff, until the potential was enough to
make it flash over.  A very subtle, but neat and unexpected display.

Dave
G2-1170

Tesla list wrote:
> 
> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>
> 
> A well known effect with dust or other particulates.  Responsible for more
> than one explosion in sites like flour mills, grain elevators, etc.
> 
> Essentially, you made a supersonic Kelvin water dropper....
> 
> Each drop carries a bit of charge, and the plethora of drops acts like the
> belt in a Van deGraaff generator.
> 
> There was a paper by Vollrath in the 30's that described some measurements
> and systems. It's of note because it's reprinted in Ford's book Homemade
> Lightning.  There are also a number of papers by French researchers on this
> technique for high voltage generation.
> 
> An acquaintance was working on a HV generator using condensing steam
> droplets, but I don't know if he ever got it working. He was attempting to
> make 1 MV at 10-20 mA DC, and getting 20-30 HP from a steam boiler is easy.