RE: OLTC II Even bigger arcs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Brett Miller <brmtesla2-at-yahoo-dot-com> 

Adam, Steve, Finn, Everyone at Derby:

That is some really amazing stuff going on there.
Hats off you all of you.  This is the stuff dreams
are made of.  We indeed live in exciting times for
the Coiling hobby.

-Brett


--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: "Adam Horden"
 > <ath-at-blueyonder.co.uk>
 >
 > Hi All,
 >
 > I got some excellent photos of Steve Conners OLTC as
 > well.
 >
 > The page is here:
 >
 > http://www.acidtech-dot-net/thon_derby_2004.phtml
 >
 > I got some shots of ground arcs as well.
 >
 > I even got one of it arcing to the primary.
 >
 > Adam Horden
 >
 > -----Original Message-----
 > From: Tesla list [mailto:tesla-at-pupman-dot-com]
 > Sent: 03 June 2004 15:09
 > To: tesla-at-pupman-dot-com
 > Subject: OLTC II Even bigger arcs
 >
 > Original poster: "Steve Conner"
 > <steve.conner-at-optosci-dot-com>
 >
 > Hi all
 >
 > Some of you might remember the OLTC II, the large
 > solid-state disruptive
 > coil that I have been working on for almost a year
 > now. It is basically
 > the
 > same as a classical coil, but with an IGBT "spark
 > gap replacement".
 >
 > I just demonstrated it at the UK Teslathon and it
 > worked great, giving
 > strikes up to 73". This was using a bang energy of
 > ~8J at 400bps. It
 > also
 > produced a couple of ground strikes (which we sadly
 > never got pictures
 > of)
 > and even struck its own primary coil, triggering the
 > overvoltage
 > protection
 > circuit. Luckily the protection circuit did its job,
 > as changing an IGBT
 > is
 > a half-hour job with a socket wrench, and cheap
 > replacements are getting
 > a
 > bit harder to find.
 >
 > The IGBTs are currently running at 2500A peak each.
 > This is twice the
 > maximum pulse rating but I expect they will take up
 > to 8000A each. So it
 > should be possible to get even more output from this
 > coil by just using
 > a
 > bigger toroid and more tank capacitance.
 >
 > But it will need a new primary circuit with lower
 > resistance, as the one
 > I'm
 > using just now, made from copper pipe and twelve
 > coax speaker cables in
 > parallel, runs dangerously hot. The MMC bank, IGBTs,
 > and secondary coil
 > only
 > get slightly warm.
 >
 >
 > Here is a great pic taken by James Pawson
 > http://www.scopeboy-dot-com/tesla/oltc2_6foot1.jpg
 >
 > There are more pics from the UK Teslathon on Mike
 > Harrison's website
 > http://www.electricstuff.co.uk/uktesla2004.html
 >
 > And you can read technical details of the OLTCII
 > here (look for Tesla
 > Four)
 > http://www.scopeboy-dot-com/tesla/
 >
 >
 >
 > A big thankyou to Terry Fritz who built the original
 > OLTC, and donated
 > parts
 > to this project too.
 >
 >
 > Steve Conner
 > Head of Power Electronics Misapplications
 > "We start with the absolute max ratings and work our
 > way up"
 >
 >