Re: Higher Mains Frequency

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

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


 > Original poster: "Steve Conner by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <steve-at-scopeboy-dot-com>
 >  >The concept indeed looks interesting, but why change an already
perfectly
 >  >working system!!!  60Hz is more than readily available - why add the
 >  >complexities of a multi-kilowatt inverter system.
 >
 > Because it's fun darnit! And educational too. People probably said the
same
 > about the SSTC when it was first invented.
 >
 > Anyway, personally I have two thoughts on this.
 >
 > 1) By driving a transformer at a higher frequency you can get more voltage
 > before it saturates. Ferinstance an MOT at 400Hz could give 12kV and (more
 > importantly) one of those little 12v:240V transformers would give 1600V.
 > Also they have chambered plastic bobbins that give good primary/secondary
 > isolation.

You might want to make some measurements with an audio signal generator (and
a stereo amp) on an MOT... iron (eddy current) losses might be significant.

 >
 > One could imagine an 'MMT' made of about a dozen of these little
 > transformers in series, maybe in oil, with the 12V primaries all in
parallel
 > driven off a half-bridge inverter that runs off the rectified 120V line.
An
 > HVDC supply would be equally easy to make by just putting a small bridge
 > rectifier and cap on each transformer and stacking them in series.



This is precisely how high voltage switching power supplies are made for
spaceflight TWTs and the ilk that require multi-kV DC supplies.  Granted,
all the secondaries are on one core, but the idea of many small individual
windings, each with it's own voltage doubler, is how it's done.  Lots of
reasons (interwinding capacitance being but one).  The typical circuit uses
"full wave" doublers (i.e. two diodes, two capacitors in series, winding
connected at the cap centertap.