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Re: Really big VTTCs

Original poster: FutureT@xxxxxxx In a message dated 1/21/07 8:52:56 PM Eastern Standard Time, tesla@xxxxxxxxxx writes:

By comparison, VTTCs seem to have topped out at a 4" x 20" secondary,
driven by one to four 833A tubes.  The consensus seems to be that you
can get just about as good performance from one 833A as with 4 of
them, if you design the coil right.  Perhaps 36" discharges seem to
be the limit for VTTCs on a good day.
Is there some physical or electronic limitation to the design and
construction of a really big VTTC?  With the availability of big
surplus power tubes (10 kW or more) on eBay, and the possibility of
multiple parallel free MOTs for input power, is there a physical
reason why no one has built a 12 x 60 or 18 x 90 VTTC?
Ten foot sword like discharges would be neat to watch!



VTTC's are not as efficient as disruptive coils so you need a lot
of power for a given spark length without staccato.   Figure

   spark length inches =  0.5*sqrt input power.

So for a 10 foot spark you need to use 60kW without staccato.
With staccato you can lower this to 20kW or so for 20PPS sparks.
But the peak power still needs the 60kWs in a sense.  It would
help to used filtered DC but it gets more dangerous and harder
to staccato control.  It can be done nicely using large tetrode tubes.
Using filtered DC you get some storage power in the filter caps.
This is similar to the DC disruptive compound storage staccato
system that I built way back when.  But in this case it's applied
to a VTTC.  I tried that too on a small scale back then.

There is no theorical limitation on VTTC output if you have
enough power to run the system.