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RE: Primary current feedback on the DRSSTC-3 (streamer loading)

Original poster: "Steve Conner" <steve.conner@xxxxxxxxxxx>

>I believe that all TC's
>exhibit this behavior, but with all the crash and bang of SGTC's, it's
>almost impossible to tell when it happens.

I noticed something similar with my DC spark gap coil. When I tuned it using
something similar to Antonio's tuner circuit (so the two coils were exactly
in tune) it really didn't work too well. As I tuned the primary lower the
sparks just kept getting bigger until a point was reached where it suddenly
failed to break out at all. I thought of taking it further with a breakout
point but I ran out of primary turns.

The hallmark of DRSSTCs seems to be long fat sparks from a small resonator.
It would be interesting to try and replicate this behaviour with a spark gap
driver. I think it can be done using DC, loose coupling, and one of these
tunings where the primary is tuned considerably below the secondary. The
loose coupling is necessary to stop all the energy being delivered to the
resonator too fast and making it flash over, and the detuning to compensate
the detuning effect of the streamer load.

I wrote a web page about this a while back


BTW- I now believe that the streamer loading mechanism we proposed for
DRSSTCs (where the streamers start growing even as energy is still being
transferred from the primary) holds true for high powered SGTCs too. This
line of thought gives a neat explanation for racing sparks with no need to
consider excitation of higher modes. In my mental model of things, the
topload voltage is dictated by the balance between energy supply from the
primary and energy output to the streamers. Tight coupling on a SGTC causes
the energy to be delivered faster than the streamers can eat it, so the top
voltage goes excessively high and that is what causes the racing sparks.

Steve C.