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Re: A Puzzle
From: DR.RESONANCE[SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent: Saturday, September 06, 1997 12:55 AM
To: Tesla List
Subject: Re: A Puzzle
Subj: Van de Graaffs
The average current from a Van de Graaff is usually less than 100
microAmps, but as Greg pointed out the peak current is many amps. Our
machine with a 30 inch (76 cm) terminal produces peak current discharges of
125 amps (for 800 nanosec) every time it fires. The peak current in amps
can easily be determined by measuring the total capacitance of the machine.
Divide the in coulombs by the time in sec (assume 1 microsec for most
machines) and this gives the total peak current in amperes.
Hope this helps out.
DR.RESONANCE-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-poodle.pupman-dot-com>
> Subject: Re: A Puzzle
> Date: Friday,September 05,1997 11:51 PM
>
>
> From: Greg Leyh[SMTP:lod-at-pacbell-dot-net]
> Sent: Friday, September 05, 1997 1:28 PM
> To: Tesla List
> Subject: Re: A Puzzle
>
> Richard Wayne Wall wrote:
>
>
> [snip]
> > Incidently, Van deGraf generators
> > produce exceedingly low current discharges. (Actually, TC discharges
> > are much like Van deGraf discharges, ie., very low current.) As we all
> > understand, voltage in a tuned quarter wave resonator reaches its
> > practical maximum and current approaches zero in the limit at the top
> > termination.
>
> Are you referring to 'arrested streamers' or discharges to ground?
> In the case of ground discharges from a Van De Graaf, I have measured
> current impulses in excess of 1500A, which caused me no end of trouble
> with nearby sensitive instruments.
>
> Regarding the current impulses in the base stem of _arrested_ streamers,
> I believe that Bert's suggestions of 1 to 10A are in the ballpark,
> probably with time structures of <10uS. With a bit of luck (and a
> Fluke ScopeMeter), perhaps I'll catch a waveform or two.
>
>
> -GL
>
>