RK05 spindle pulleys - trade 50Hz vs 60Hz?

Anders Nelson anders.k.nelson at gmail.com
Thu Jul 26 09:54:00 CDT 2018

To get that power, did they have to use a rotary convertor from 60Hz
3-phase to get 400Hz?


Anders Nelson

+1 (517) 775-6129


On Thu, Jul 26, 2018 at 10:49 AM Paul Koning via cctalk <
cctalk at classiccmp.org> wrote:

> > On Jul 26, 2018, at 9:55 AM, W2HX via cctalk <cctalk at classiccmp.org>
> wrote:
> >
> > That is not the whole story of 400Hz. The other part of that story is
> that now, all of the downstream equipment that uses the 400 Hz can have
> much simpler AC to DC power supplies in them. At 400 Hz it is much easier
> to regulate and filter out ripple. So instead of every piece of equipment
> each having lots of large capacitors, now they only need small capacitors.
> Space is at a premium as well as weight on a plane.
> This even applies to some terrestrial equipment.  CDC used 400 Hz 3-phase
> power for the 6000 series mainframes.  3-phase power cuts the ripple by a
> large fraction and raises the ripple frequency 3x; 400 Hz instead of 60 or
> 50 raises the ripple frequency further by that ratio.  So high power
> supplies get much smaller, both in the transformers and in the filter
> capacitors.
> The 400 Hz came from motor-generators.  Those also clean up the power a
> lot, because any spikes or brief dips are absorbed by the mechanical
> intertia and don't appear on the output.
>         paul

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