On 1/3/22 10:58 AM, Paul Koning via cctalk wrote: > The discussion about 3-phase made me check some documentation.
> I also looked at some CDC 6000 series docs. Those used 400 Hz 3 phase for > supplying the CPU and peripheral logic. The CPU cabinets also take 3 phase > mains power for the compressors (for the Freon cooling system). Curiously, > the 1964-era 6603 disk drive uses only 400 Hz power. I wonder if that feeds > the spindle motor, or if that was a DC motor? And the 626 tape drive wants > 3-phase mains power. Are you certain about that? The '66 document for the Bryant series I drives/6603 http://bitsavers.org/pdf/bryant60127000B_Bryant4000_ServiceHbk_Oct66.pdf on page 1-3 mentions 280/440 3-phase just for the spindle motor (5 or 10 hp, depending on number of disks). The hydraulic pump had its own 3-phase motor. I think the 6603 electronics were 400Hz. Serious current draw on those motor lines too--the Series II shows power consumption draw at 280VAC--somewhere around 50A. I remember the leak jugs--and the hydraulic fluid that occasionally made it onto the floor. An operator at SVLOPS made a dash to take care of a 501 printer and slipped and fell in a puddle of the stuff. It was funny at the time... The old 808/6638 drives, which displaced the 6603, similarly used 280V 3-phase for the 5 hp spindle motor and hydraulic pump and 440Hz for the electronics. The 821 was sort of a double-capacity version of the 808. Other than for a few units, it never made it to general distribution, being rendered obsolete by the 844 disk pack drives. I recall that CDC qualified for a lucrative contract by dint of Mike Miller noticing that one of the 821s had gone offline and doing a 100 yard sprint to punch the button. CDC qualified by a matter of seconds. --Chuck
