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Re: Marx Generator



Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <Tesla729-at-cs-dot-com>

In a message dated 4/28/03 11:29:31 AM Pacific Daylight Time, 
tesla-at-pupman-dot-com writes:
>Original poster: "Dr. Resonance by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>
>
>If you are going for a 1 MEV output you should charge at around 100 kV per
>stage x 10 stages.  You will need a 100 kV DC power source rated around 5-10
>kVA to do an efficient job.
>
>Trying to go this high with a flyback circuit and only a few mA won't work.
>The leakage currents may exceed you power supply's ability to charge the cap
>bank, and also, after 20-25 stages the efficiency level becomes rather low.
>Leakage currents inside caps and also on connections multiply as additional
>stages are added.


Dr. Resonance, all,

Wow, a 1 megavolt Marx generator sounds like an expen$ive project.
I do have a 140 kVp, 500 mA x-ray transformer that, with proper rec-
tification, would probably fit the bill :^) This oil-filled monster tips the
scales at nearly 1000 lbs. and, with proper external ballasting, makes
for one heckuva Jacob's ladder driver. I know that the ratings of x-ray
trannies are for low duty cycle but I feel reasonable sure that my x-
ray tranny could easily handle 5 to 10 kVA continuous with NO problem.
I run my Jacob's ladder with the narrowest part of the gap at ~8" and then
the rails spread out to about 20" at the top and with the variac turned
to only about 60% of 240 volt input, it will easily break down the 8"
spacing and climb some 42" to the top where the rails are about
20" apart. And this will draw a good 50 to 60 amps from the wall.
The underrated 240 volt, 30 amp variac gets hot long before the
transformer even starts to get warm while doing this.

I suppose the most expensive part would be trying to obtain the
10 to 15 identical >100 kV rated pulse caps. And I'm sure we're not
talking about a few hundred pfd each either - probably more like
at least several nfd minimum or a sizable fraction of a ufd.

And then obtaining rectifiers that are sufficiently robust to handle
these kinds of voltages and reversal voltages from the discharge.
Not to mention the huge inductive filtering that would be required :^O
Sounds like it may be pretty well beyond the budgets of MOST
of us :^(

And last, but not least, this would be EXTREMELY DANGEROUS !!
One mishapped zap would be literally comparable to being
struck by a lightning bolt! And the noise level of the discharge
would probably be comparable to the report of a 105 mm Howitzer!

Maybe 1 MV is a bit high of a goal for a Marx generator for a
novice experimenter without access to a REAL HV laboratory :^/

Sparking in Memphis,
David Rieben