Motor generator

Jay Jaeger cube1 at
Wed May 5 20:40:25 CDT 2021

On 5/5/2021 7:18 PM, Jules Richardson via cctalk wrote:
> On 5/5/21 6:09 AM, Mark Linimon via cctalk wrote:
>> On Tue, May 04, 2021 at 10:07:28PM -0700, Chuck Guzis via cctech wrote:
>>> "Power for the basic computer consists of one 250 kva, 400 Hz motor
>>> generator set.  The motor-generator set has the capability of providing
>>> power for the CPU, MCS, I/O and the MCU. The optional memory requires
>>> the addition of an 80 kva motor-generator set."
>> I'm looking at this RISC-V board sitting here on my desk (with its
>> "massive" 2-inch-long heat sink) and shaking my head at how far we have
>> come.
> I seem to recall an anecdote about Acorn hooking up the first prototype 
> ARM-1 processor and it working, despite showing no current draw on the 
> connected ammeter - it then transpired that the power supply was still 
> switched off,  but it was so efficient that it was able to run via 
> leakage current on the connected I/O lines.
> Jules

While I was in grad school at U.W. (the one in Wisconsin) we had 
obtained via surplus an IBM 7094 II from military surplus - I seem to 
recall WSMR (White Sands Missle Range).  Of course, it had an MG.  We 
got it put together and with a replaced transistor here and there (one 
of which was modern silicon) we got it running.  We had NO peripherals, 
but my friend Paul came up with the idea to use a sense switch to talk 
RS-232 at 9600bps, and using that he got the Purdue University Fast 
FORTRAN Translator (PUFFT)loaded and up and running, and I wrote some 
support code on a Datacraft 6024 to send it card images and receive 
print lines.

One evening after supper I convinced my wife to let me head down to the 
CS building and play.  I stepped into the CS building and man, there was 
a lot of smokey smell and obvious evidence of smoke - but no alarms.  It 
got worse as I headed down towards the basement where we had the gear 
set up.  It turned out one of the bearings in the MG had welded itself 
to the shaft (and not for lack of proper lubrication).  Thing was about 
5" in diameter.  That put us out of commission for a while, until many 
months later the UW Machine shop fixed it up.

Not too long after that machine, and an IBM 1410 that had been donated 
by Oscar Mayer were sold off to a place in Ohio where they actually were 
still using that second hand gear in 1977 - and it was that very same 
outfit that we visited decades later and recovered the IBM 1410 PR155 
operating system tape and diagnostics, a copy of OS/360,  and other 
interesting stuff.


More information about the cctech mailing list