Humongous SSTC (was SSTC hits 66" )

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

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

 >the switching loss can be pretty bad before you get
 >less sparks/IGBT than an OLTC ;-)

go on rub it in :( :P But the switching losses for the big bricks _are_ bad,
I was looking at a datasheet for a 3.3kV 1200A unit, and the losses are
quoted in J, not the usual mJ.

I'm also thinking I was too kind with the peak current in my OLTC stuff, I'm
going to double it and see what happens :)

*

 >I should think that if one is spending the bucks for all those IGBT bricks,
 >that investing in a surplus 20 HP 3 phase motor to make 3 phases from 1
 >wouldn't be a big deal.

The 3 phase power is not necessary. All the system basically needs is 600V
DC at like 20A :-o and directly rectifying a 3 phase 415V line happens to be
the most convenient way of doing that. (415= 240 sqrt(3) is the standard
voltage for 3 phase here in UK)

A 240 to 415V step-up transformer driving a single phase rectifier would
work just as well, albeit with a worse power factor. So would throwing a
wire over the nearest tram lines :))

Also, I don't think anyone would buy large IGBT bricks brand new for a job
like this. Last time I tried, you could get four used but good CM600s for
$50. This makes them cheap compared to the capacitor banks: one massive
electrolytic bank (something like 20000uF -at- 600v) and a large MMC. Caps are
harder to get surplus, because railgun and coilgun hobbyists buy up all the
electrolytics and Tesla coilers buy all the pulse ones.

I think the situation has changed though, thanks to our efforts in
popularising big SSTCs, Tesla coilers are now buying up all the surplus
CM600s too :(

Steve C.