Primary Switching [was RE: SSTC hits 66"]

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

Original poster: Greg Leyh <lod-at-pacbell-dot-net> 

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.

As far as settling on a suitable primary drive scheme for ALF, there's 
still plenty of choices to consider.  A large rotary/static quench gap 
array was the first choice, but was abandoned a few years ago after the 
4.5kV IGBTs nicely proved themselves in 4000A pulsed service -- mores the 
pity, as the 50' long gap arrays would have been the most visually 
compelling.  The 6.5kV IGBT silicon is the most attractive approach at 
present, as LASCRs still have recovery times of 100's of uS. This long 
recovery time would be problematic, even at a resonant frequency of 6.9kHz.
9.5kV IGBT silicon is now on the horizon as well, though there's the 
concern it will have unacceptably high forward losses due to the doping 
used to increase the punchthrough.

Monolithic Diamond Switch technology looks *very* promising, but it may be 
awhile before it's fully mature; they're still in Phase II of SBIR 
development.  Perhaps by the time ALF is funded, MDS will be the technology 
of choice.  <emote>

And yes, 12kV 3PH would probably be the appropriate feeder class, for 
either long-haul or onsite generation scenarios.



>Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com>
> >If I didn't want Steve W. to succeed, I would have suggested
> >adding a series
> >resistor instead of capacitor <emote>
>
>ROTFLMAO :D but would Steve have fallen for it...
>
> >Maybe we should find a way to work together and build an electrum sized
> >coil <emote>
>
>Don't laugh... I reckon it is possible in theory to build a DRSSTC or OLTC
>of that size. And some mad b*****d will do it sooner or later. In fact I
>heard that Greg Leyh had decided to build his ALF monster twin coil as an
>OLTC, using banks of 6.6kV 3000A IGBTs or similar. I suppose the "line" he's
>running "off" would be a 12kV three-phase feeder ::)