a much simpler approach is to have a counter (base 3 would be good) so you
can turn on each phase in sequence. Drive it with an oscillator and you
have variable frequency.
But, you will have incredibly nasty harmonics and it won't be kind to
motors.

A "single phase" example of this kind of converter is the CD ignition
schematic on my web page (www.wbnoble.com, look under "articles I wrote") -
it works nicely, I built it because I couldn't find anything commercially,
but it has a major amount of RFI - multiply the power levels by 1000 and you
will seriously annoy the neighbors.

There are books written on commutating circuits and power inverters - you
need to at least somewhat approximate a sine wave - 3 transistors per phase
will give you 8 levels, that ought to be enough (think binary, 2**3 = 8),
just add snubber circuits and logic


"Ignoramus17647" wrote in message
...
On Mon, 14 Feb 2005 20:22:37 GMT, Jerry Martes
wrote:
I like your idea of synchronizing the three output voltages by
triggering
them with a rotating machine.

I am glad to hear it.

But, are you able to manufacture the three output voltage sources??

I do not understand the question.

The schematic is that input voltage will be converted to appropriate
voltage, then rectified to DC, then rectified DC will be inverted by
three inverters, according to what the rotating cylinder tells the
transistors (120 degree shift). The inverted current will then be
again transformed with isolation transformers, with three output legs
tied with a common neutral.

Which parts of this scheme are you referring to?

i