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Re: SSTC theory
Original poster: "Antonio Carlos M. de Queiroz" <acmdq-at-uol-dot-com.br>
Tesla list wrote:
> Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz>
> I don't think I was ever convinced that streamer loading was a
> culprit. The typical operation mode is to ring the secondary up until
> it lets go and one usually designs the secondary to not let go until
> the bulk of primary energy has reached it (at which point there is
> little left in the primary to transfer). In my opinion, recent
> attempts to use matching theory are valid only if one wants to feed a
> continuous arc in CW operation. I seriously doubt its validity when
> applied to either classic disruptive coils or the ISSTC which is
> pretty much the same thing when examining the operation of the
> secondary in such coils. Past experience with my disruptive coils
> often (if not always) showed better results with the primary tuned to
> what would have been the LSB generated with the tunings equal. This
> was referred to in the past as "offset tuning" and has appeared in
> early papers on TCs. I forget which ones but I have seen voltage vs
> tuning graphs in some of them. I still have those papers buried in a
> mountain at home.
Really, considering that:
1) The load is seriously nonlinear, and only effectively appears after
2) Most systems are not operated continuously, but in short bursts,
maybe just short enough to build up enough energy in the secondary
system for breakout.
Something that shall be looked in the design is then what happens
while the output voltage is rising, in a condition of, ideally, no
load. The ideal would be to always present a resistive impedance to
the driver while in this condition.
But this is precisely what happens if the load is removed from the
"matching theory" design. The input current is always in phase with
the input voltage while the output voltage is rising. If the energy is
not spent, after some cycles, the output voltage reaches a maximum
(of about two times the designed output voltage) and starts to fall.
While it is falling the input current is in opposite
phase to the input voltage, returning energy to the power supply.
I will see if I can work out the details of the curious waveforms
that appear, and see if they are naturally in this way, or are
forced to this way by the matched design, that appears to work well in
this aspect too.
Antonio Carlos M. de Queiroz