RK05 spindle pulleys - trade 50Hz vs 60Hz?

[Anders Nelson]

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Anders Nelson

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www.erogear.com


On Thu, Jul 26, 2018 at 11:14 AM Chuck Guzis via cctalk <
cctalk at classiccmp.org> wrote:

> On 07/26/2018 07:54 AM, Anders Nelson via cctalk wrote:
> > To get that power, did they have to use a rotary convertor from 60Hz
> > 3-phase to get 400Hz?
> >
> > https://en.wikipedia.org/wiki/Rotary_converter
>
> As Paul mentioned, less a "rotary converter" than a AC motor-AC
> generator hookup.  One advantage is that the rotational inertia in such
> a setup does have the ability to smooth over small power disruptions.
>
> Such MG setups were very common in industry before modern
> semiconductors.  When I had a summer job showing movies at a drive-in
> theater (a long time ago), the supply for the carbon-arc lamps was a
> 40hp motor powered by 3-phase 60Hz, driving a DC generator.  In WWII
> radio equipment, MGs in a unitzed form called "dynamotors" were used to
> supply the high-voltage anode voltage for the tubes.  Electroplating
> shops similarly used large DC generator setups to supply plating current.
>
> 3 phase full-wave rectified AC has approximately 87% DC content at 6x
> the supply frequency.  So for 400Hz, the ripple is only 13 percent at
> 2400 Hz before filtering.
>
> --Chuck
>
>