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MOT Powered SSTC - First Tests Successful!!



Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>

Utilizing my solid state switch circuit which was posted previously, my
initial tests of my new SSTC are successful!!

One of the biggest problems in SSTC coiling I see right now is the fact that
most everyone (including myself)  is using the full-bridge topology to drive
their SSTC coils.
This design works extremely well and is well documented through the web.
This is probably the reason most tend to start with this topology (again
including myself.)
But this design is flawed as it extremely limits the output of your SSTC as
input voltages are relatively low (< 240VAC typically)  Many individuals try
to improve upon the full-bridge
topology by adding elaborate feedback schemes and other efficiency
increasing changes, but this may buy you a few inches output at most.  To
get big output on a SSTC, you need
big voltage input.  Just like its big brother, the conventional tesla coil,
brute force (voltage) is what is needed for big output.

My new SSTC works exactly the same way as the typical full-bridge driven
SSTC except it uses a much simpler, series stacked FET array to switch high
voltages.  Its an extremely
simple design as well although the FETs, and some of the high voltage
resistors are fairly expensive.

I performed my first test this morning and the results are spectacular.  My
switching frequency was about 190kHz, input power at about 2kW but limited
to only 75% of rated output
voltage of my 2.4kVAC MOT (microwave oven transformer)  Using the MOT, which
is half-rectified (no filter capacitors), output was well over 30" !   I
didn't go to 100% as with only a voltage rating of 4000V across the FETs and
3600V across my TVRs, 2.4kVAC half-rectified would be pushing it a bit.  I
may add a fifth FET when I get finalized PCB artwork done for this design
(right now I'm using prototype brass-board).

Here is my current high voltage switch schematic which is placed between my
primary coil and ground.

http://www.spacecatlighting-dot-com/datasheets/sstc3_sch02.pdf

I'll be posting my system schematic, oscillator gate driver schematic, and
pictures soon.

The Captain