RE: Primary Switching [was RE: SSTC hits 66"]

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

Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >Unfortunately ALF cannot operate as elegantly as an OLTC; there will need
 >to be command charging circuitry between the cap banks and the prime power
 >source.

But it's still going to be the same idea as an OLTC? A classic disruptive
coil circuit with DC charging and IGBTs in place of the spark gap? I presume
the plan is to use some sort of commercial capacitor charging power supply
like the ones used for laser flashlamps etc? Maybe you could "borrow" the
power supply out of NOVA :))

I tried to get a couple of these flashlamp power supplies for my OLTC.
ASTRON (iirc) make a nice 1kV 2000W unit for YAG lasers. But unfortunately
they were too pricey even used on eBay, and the ones I saw all had a
negative output polarity :(( So I ended up with old-fashioned resonant
charging and no command facility.

If you have any more information on ALF apart from the stuff on your website
(either the full sized facility or the scale model) I'd be very interested
to see it and I'm sure many others would too.

BTW, Greg's two papers on IGBT brick pulse operation were another of the
things that motivated pulsed SSTC development. He did some very nasty things
to IGBT bricks, like hard switching pulse currents of several times the
maximum rating. This resulted in di/dt's far higher than you would see in
pulsed SSTC work. But (IIRC) the IGBTs did not fail unless the gate drive
was too low for the required current and they came out of saturation.

Steve C.