Control Data 841 disk drive's 3-phase power supply resurrection

[Paul Koning]

> On Feb 18, 2018, at 11:02 PM, Chuck Guzis via cctalk <cctalk at classiccmp.org> wrote:
> 
> On 02/18/2018 04:55 PM, Al Kossow via cctalk wrote:
>> 
>> 
>> On 2/18/18 4:07 PM, Chuck Guzis via cctalk wrote:
>> 
>>> Generally, the electromechanical stuff (motors) was run from 208V
>>> 3-phase and often, the electronics from 400Hz.
>>> 
>>> At least that's what I recall.
>>> 
>>> --Chuck
>>> 
>> 
>> that isn't what the schematic looks like.
>> there is a low voltage transformer hung off one of the phases
> 
> Perhaps that's only for controllers and CPUs and such.  It's been too
> long...

It varies.  Looking at CDC 6600 CPU cabinet power schematics, you can see 400 Hz 3 phase powering the DC supplies, and 50/60 Hz three phase for the cooling system compressors.  An interesting detail is that the DC supplies seem to be unregulated, with choke input filters.  That makes some sense, the load is reasonably constant with the logic used in the 6600, and choke input supplies have decent regulation.

The DD60 console takes 400 Hz 3 phase for the high voltage supply, and uses 60 Hz single phase (120 volt) for the other supplies.

	paul