Inspired by OLTC

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

Original poster: "K. C. Herrick by way of Terry Fritz <twftesla-at-qwest-dot-net>" <kchdlh-at-juno-dot-com>

Here's how I see reconfiguring my s.s.t.c. primary for low-low-resistance
and high-high-current--if Terry will accomodate me with
http://hot-streamer-dot-com/temp/TCH.gif.  

1.  The switching off-line power supplies keep the 8 capacitors charged
to ~160 V each.  They are isolated for rf by small inductors from the 4
pairs of copper-pipe or -strap primary segments that interconnect the
capacitors.

2.  Each of the 8 groups of paralleled MOSFETs is connected via low-Z
means to the primary segments/capacitors, as shown.  Each MOSFET is
associated with an external fast diode and a series Schottky diode, thus
keeping its slow substrate-diode out of conduction.

3.  As my patent explains, all the outside MOSFETs turning on together
cause 4 capacitors to be connected in series through 1 set of primary
segments, creating current flow in one direction.  The inner MOSFETs do
the opposite.  The circuit is untuned.

4.  Inner & outer MOSFETs are driven via crossover-control circuits so
that they are never on at the same time.  During each brief interval
between half-cycles when none are on, the fast diodes act to clamp the
inductive kick of the primary coil, as seen by any MOSFET, to twice the
voltage of a capacitor.  Further, any voltage induced by the secondary
back into the primary, either during those intervals or after excitation
is cut off, or voltage generated by the primary at drive cut-off, is
similarly clamped.

5.  Each group of MOSFETs is driven via transformer-coupling, not shown,
and all drive signals derive from the phase-shifted, amplified and
appropriately-gated secondary-return current.  This makes the entire
circuit a gated feedback-oscillator, with the Fr of the secondary being
the sole frequency-determining factor.  Thus, it never needs tuning.

6.  The configuration can, of course, be adapted for more
MOSFET/capacitor groups.  And also, the 160 V could be increased, with
higher-voltage-rated MOSFETs (my present one being 500 V).

Anyone interested should not be put off by my patent.  That would be a
consideration only for commercial use within the U.S.  And fat chance of
that; I took it out primarily for the exercise.  (Herrick's Last Patent,
for dam' sure.)

Ken Herrick