> On May 4, 2021, at 7:53 PM, Carlos E Murillo-Sanchez via cctalk
> <cctalk@classiccmp.org> wrote:
>
> Donald via cctalk wrote:
>> In the deep recesses of my mind I seem to remember something about S/360
>> machines using a motor generator.
>>
>>
>> If I am right was this to create a stable power source at a certain
>> frequency or voltage?
> Those systems predate my experience by roughly 25-30 years. But once you go
> through the trouble of adding such a thing as a motor-generator, then you can
> make the generator a poly-phase device (say, 12-phase) and get a much lower
> ripple in a full-wave polyphase rectifier; you can also easily control the
> output voltage by acting on the generator's rotor field current. This sort
> of equipment is used for industrial processes requiring DC at thousands of
> amps; the polyphase setup makes it possible to leave out the output filter
> capacitors.
Polyphase would be complex, adding more generator windings, wires, and power
transformer windings. The usual approach instead is to increase the frequency,
which is easy to do. 400 Hz is a standard frequency for applications where
transformer weight is a concern, so it's found in airplanes among other things.
paul
