Re: FREE TO A GOOD HOME

From: Lord Isildur (isildur_at_andrew.cmu.edu)
Date: 05/24/03 

Date: Sat, 24 May 2003 10:46:18 -0400 (EDT)

the fujitsu eagles, i think, ran on 3-phase. a friend of mine
told me a story from when he was in high school, working as an operator
in a machine room at CMU.. there was a power failure, and racks full of
eagles began spinning down.. the whole room just hummed its tone lower and
lower.. ad then the power came back on. All the drives came back up in
phase, except one. The power had been out for maybe 15 seconds. The disks
were still spinning at maybe 2000 rpm or so. and the one that came up out of
phase stopped, instantly. Terrible noise. Disk dead. The platters had all
bent from the inerta dump.. :)

isildur

On Sat, 24 May 2003, Michael Moroney wrote:

> Chris Olive <nospam@raytheon.com> writes:
>
> >Huh... could have sworn a 750 ran on 3-phase... 8-/
>
> Not the 750 itself, but some old disk drives of that era apparently did.
> A long-time Deccie was telling me just today about these drives with
> three phase drive motors.. wouldn't even spin on single phase.
>
> One model was smart enough to not spin if the phasing was reversed,
> the other would spin _backwards_ (but was smart enough not to load the
> heads). Forget which drives those were.
>
> DEC always overbuilt everything power-related in those days. Probably
> lots of 750s came with 3 phase 30+A power cords even though they could
> actually be powered off a single phase 15A home circuit. Look in the
> old hardware, most of those mega power feeds went to a controller with
> a bunch of ordinary single phase outlets, and all the subcomponents of
> the computer were plugged into those outlets.
>
> -Mike
>

Relevant Pages

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