Re: TC powered by LV Marx generator?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>

I'll have to pick up some SIDACs and small caps and
tinker with this idea, then.  Got a pole pig already.
Granted, I haven't used it in a TC, but someday I
will!  Working on a PT-based coil right now.  As for
the Marx-powered coil, that was my crack at an OLTC
kind of "transformerless" coil idea.  I'm sure nobody
builds OLTCs because they can't find big HV
transformers :)  Rather, they build them because of
their unique properties/construction.

--- Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>
>
>
> ----- Original Message -----
> From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Wednesday, April 20, 2005 11:04 AM
> Subject: TC powered by LV Marx generator?
>
>
>  > Original poster: "J. Aaron Holmes"
> <jaholmes@xxxxxxxxxxxxxxxxxx>
>  >
>  > Whilst reading a couple of the few (and generally
>  > lame) web sites about Marx generators, and having
> seen
>  > some list traffic about OLTCs, I got to wondering
>  > about a hybrid of the two ideas, specifically...
>  >
>  > ...would it be possible to construct a
> "low-voltage"
>  > Marx generator using SIDACs or MOVs or something
>  > instead of the traditional spark gaps in each
> stage?
>
>
> MOVs have a high voltage drop (i.e. they're not like
> a spark gap that drops
> to a low voltage after firing) so they'd be
> inappropriate.  The power
> dissipation would be huge, and the bank wouldn't
> erect like you want.
>
> SIDACs or avalanche transistors and such like have
> been used in the past for
> low voltage  Marx type schemes.
>
> There are a fair number of charge in parallel
> discharge in series switching
> schemes around.  I suspect that they all work, but
> are more complex and
> expensive than just buying a higher voltage
> transformer. If you're thinking
> about the <20kVA class of system, surplus pole
> transformers at a few hundred
> dollars is pretty hard to beat.
>
> Now, as an exercise in curiosity, though, you could
> build almost anything
> you want.  It would certainly be interesting, and
> has some intriguing
> aspects.For instance, rather than an MMC with 10
> capacitors in series hooked
> to a multigap with 10 gaps in series, why not
> intertwine the two in a marx
> configuration, charged from a 2 kV source instead of
> a 20kV source.  You'd
> probably want to use inductors rather than resistors
> in the charging chain.
> And, you'd need to pick your values carefully so
> that the current through
> the charging components isn't bigger than through
> your external primary.
>
> I believe one of the list posters had actually
> worked out a clever scheme
> using a segmented primary coil, taking the
> distributed idea even further.
> Maybe 3 or 4 years ago?
>
>
>
>  > With a dozen or so stages, such a thing might be
> able
>  > to create a couple of kV from the 120-volt AC
> line.
>  > Further, if such a thing *did* work, it would
> just beg
>  > to be connected to a very small SGTC, with the
> caps in
>  > the Marx doubling as the cap for the TC.
> Granted,
>  > this would probably not provide for a coil with
>  > continuous output, but it would be interesting
>  > nonetheless.
>  >
>  > I was going to post the Marx-related part of this
>  > question to hvlist, but I have twice attempted to
>  > subscribe to hvlist and failed (I send
> "subscribe"
>  > mail and nothing happens).  No word from Chip
> yet,
>  > either :(
>  >
>  > 73,
>  > Aaron, N7OE
>  >
>  >
>
>
>