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

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

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

Here's the website of the company developing the MDS technology, they're 
just across the bay from us:
http://www.aasc-dot-net/PreCommDev/overview.htm

The diamond switch overview is in the last paragraph.  There's also a brief 
outline of the specs:
http://www.aasc-dot-net/PreCommDev/switch.htm

Regarding the 1:12 scale prototype, yes it's currently underway... although 
it's fairly low on the priority stack right now.  The secondary towers and 
the toroids are finished, as well as the primary drive modules [3.2kV, 
2.7kA each tower].  The system still lacks the primary forms, stands, 
cables and the main control box.  There's also a collection of 1:12 scale 
people figurines for the coil as well, to 'flesh out' the diarama properly.


>Original poster: jimmy hynes <chunkyboy86-at-yahoo-dot-com>
>Hi,
>
>What's the deal on the monolithic diamond switches? I couldn't pick up 
>much information from
>google.
>
>Are you still planning on doing the smaller prototype of it?

>--- Tesla list <tesla-at-pupman-dot-com> wrote:
> > 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.