Motor generator

Chuck Guzis cclist at
Wed May 5 10:36:27 CDT 2021

On 5/5/21 5:18 AM, Paul Koning wrote:

> An earlier message commented on the whine from power converters.  I
> don't know how common this practice was, but at the University of
> Illinois PLATO system which had a pair of 6500 systems, the
> motor-generator was located near the elevator machinery in a corner
> of the building, far from the computer room.  Yes, it was noisy, but
> no one spent any time in that location.  The computer room was -- by
> mainframe standards certainly -- rather quiet.  Of course it helps to
> have liquid cooling, so there weren't many noisy fans to deal with.

It was the "white noise" from the vacuum pumps in the tape drive banks
that drove me nuts after a few hours.  After 8 hours or so, I sometimes
found my hands shaking.  Of course this facility had a very large
machine floor with several full-sized installations.  Eventually,
management provided ear protection.

As far as any "whine"--I vaguely recall hearing a high-pitched whine if
I put my ear close to the power adjustment panel in a CDC Cyber--but it
was barely audible.

As far as the MG sets themselves, I never went there--any noise at
SVLOPE was drowned out by the fans in the cooling tower.  I don't recall
where the power equipment at ARHOPS was located.


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