Re: The Next Coil
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Sunday, August 03, 1997 3:52 PM
Subject: Re: The Next Coil
Hi Bert, Greg, all,
> From: Greg Leyh[SMTP:lod-at-pacbell-dot-net]
> Sent: Friday, August 01, 1997 5:08 PM
> To: Tesla List
> Subject: Re: The Next Coil
> Bert Hickman wrote:
> > > As part of a quickie experiment, I wanted to add C to the coil without
> > > affecting the breakout voltage of the toroid. After rooting around in
> > > the junk boxes for awhile I found a bag of big doorknob-style caps out of
> > > a laser power supply. I stacked twenty of these capacitors, each one
> > > rated at 2200pF -at-30kV, using threaded 3" standoffs between them. The
> > > finished stack, which measured about 10' in length, was then placed inside
> > > of the secondary along the center axis.
> > > Each cap had a 10Mohm stick resistor in parallel.
> > > -GL
> > Greg,
> > EXCELLENT! This is the first hard evidence that streamer propagation for
> > HF AC discharges is significantly enhanced by providing a low impedance
> > source of "instant" charge from a lumped C and not a "higher impedance"
> > distributed C! Although large toroids have seemingly "worked" better for
> > most coils, even though they may reduce peak output voltage, until now
> > there was only hand waving arguments as to possible causes.
> > Greg, you also made one heck of a nice voltage divider - by any chance
> > did you happen to measure the resulting voltage across the bottom-most
> > cap? With this, and the other known input parameters, you'd know your
> > coil efficiency (perhaps helping to resolves some earlier/animated
> > discussions of coupling, output voltages, and efficiencies!)
> Whoops! No, I did not. Wouldn't the divider drag the voltage down by a
> considerable amount, anyway? At least I know that the voltage is less
> than 600kV...
It would have been interesting to see just what you were getting
voltage-wise with the streamers though. I for one would be most
interested in the result.