Motor generator

[Jon Elson]

On 05/05/2021 12:07 AM, Chuck Guzis via cctalk wrote:
> Small S/360 systems were operated from standard AC distribution.  I
> don't know where the breakover was for IBM S/360; probably not for the
> model 30, 40, or 75.   The 195, I suspect did use an MG set.
>
>
"Real" 360's did not use MG sets.  By real, I mean the ones 
built with SLT technology, the discrete transistors and 
diodes on 1/2" square ceramic hybrid modules.  The logic was 
essentially DTL.  As best as I can figure, the 360/20, /30, 
and /40 used some 60 Hz transformer power supplies.  (Same 
for the /22 and /25, later replacements for the model /30.)  
I'm not so sure about the model /44, a non-microcoded and 
stripped-down machine intended for process control.  (No 
decimal or character instructions.)
The /44 was a pretty big machine, about the same size as a 
360/50.

The /50 and /65 definitely used the converter-inverter 
system to supply the logic power supplies with 120 V 2500 Hz 
regulated sine wave power.  I would guess the model /75 used 
the same scheme.

The 360/85 was a prototype of the 370/165, and was built 
with IBM's own take on ECL, called MST.
It was water-cooled, and ran from 415 Hz power.  The /85 was 
slightly repackaged to become the
370/165, and used larger static RAMs in the cache and 
control store.  But, it was still quite similar.

The 360/91 and /95 were the same CPU, but the /95 had a 
non-destructive readout memory system, which offered higher 
speed due to not needing a writeback of just-read data.  
These were built with an ECL variant, but using a packaging 
technology similar to SLT.  There isn't a whole lot of 
detail on the hardware of these machines.  They were 
supercomputers, not microcoded, and with multiple functional 
units, out of order execution, etc.  The basic design was 
later redone with MST for the model 195.  These all ran off 
415 Hz power, I think.  most installations had massive UPSes 
for them.

Jon