Re: High-input SSTC: Possible?

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Matthew,

It certainly is possible!  I did a lot of work in this area a while back:

http://hot-streamer-dot-com/TeslaCoils/MyCoils/SolidStateCoil/

Using an array of many IGBTs, a typical high voltage spark gap can be
replaced with for more efficient solid state electronics.  I was able to
get 1000V and 150 amps (at the same time) through a single IGBT safely.  By
putting them in parallel for higher current and in series for higher
voltage, you can make a fully solid state gap that will run the "big boy"
high voltage disruptive coils.

Unfortunately, it is very expensive.  I estimated about $2000 on top of any
R&D setbacks.  Recently, higher power (voltage) IGBTs are becoming
available that would really reduce the price greatly.  So I am sort of
sitting till I can get the price down.  You need a bidirectional 25000 volt
500 amp switch that can turn on in 1 millionth of a second and turn off at
any time during the firing cycle while fully protecting itself from damage.
 The art "can" do that (but it breaks a sweat :-)) but not at amateur cost
targets...

The IGBTs are fired by fiber optics going to IGBT driver chips.  Any gap
type (sync, single shot, async) can easily be reproduced with simple
electronics.

While I don't think the technology is ready for general use and not quite
ready for even bleeding edge experimental use, Solid state gaps will soon
be here. :-)))

BTW - Solid state spark gap are very quiet (they softly click due to
high-current switching) and dark which is very odd compared to a loud
bright flashing spark gap.  A conventional gap can easily waste 1/2 of a
coil's power.  SSgaps promise far higher energy throughput to the streamers
were it belongs!

Cheers,

	Terry




At 10:25 AM 12/23/2001 +1030, you wrote:
>Hi all
>
>Looking at various SSTC schematics, I see that we are generally
>switching about 120V; is it possible to use a stack of MOSFETs, or
>whatever, to work with a larger power source, eg., rectified MOT, to
>build an SSTC with a lot more "oomph"?
>
>Cheers
>
>Matthew Smith
>