3 Jan
2022
3 Jan
'22
12:36 p.m.
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