[time-nuts] The home time-lab

albertson.chris at gmail.com albertson.chris at gmail.com
Tue Jul 26 20:08:15 EDT 2016

I remember the 91. The MG Produced 400Hz power. It is easier to build a linear power supply as it would use smaller transformers and need less filtering

The chilled water cooling was not the best idea because when they had to power down water would condense  on the insides and they would have to wait for it to dry befor powering up

The CDC 6600 in the other room used freon and did not have that problem. You could power cycle it in maybe 15 minutes

But a water cool machine had tons of cold water inside after the power is removed

Bothe were antiques when I used them in early 80s

> On Jul 26, 2016, at 10:01 AM, Francis Grosz <fgrosz at otiengineering.com> wrote:
> Jim,
>     IIRC, the IBM 360 mod 91 was one that used a MG set.  I think it also
> required chilled distilled water for cooling.  Those were indeed the
> days of "Big Iron".
>         Francis Grosz
>> Date: Mon, 25 Jul 2016 21:04:58 -0700
>> From: jimlux <jimlux at earthlink.net>
>> To: time-nuts at febo.com
>> Subject: Re: [time-nuts] The home time-lab
>> Message-ID: <ec93c0e5-8f49-05e3-7042-917c179d594d at earthlink.net>
>> Content-Type: text/plain; charset=utf-8; format=flowed
>> On 7/25/16 6:55 AM, Bob Camp wrote:
>> Hi
>> If you go back far enough in time
> . there is another alternative:
>>       Big rectifier bank, turning AC into DC, often off of multiple
> phases or sources.
>>       Big DC motor running into a fairly large flywheel.
>>       AC generator (or in some cases DC generators) running off of the
> shaft
>>       A tuning fork (yes state of the art timing) based control on the
> AC output frequency
>>       A saturated reactor control loop on the generator side, same
> thing on the motor side.
>> Wonderfull stuff. State of the art UPS for your shipboard computer in
> 1962. Ear muffs anyone?
>> Bob
>> we had a system like this to turn 60 Hz into 50 Hz with a toothed belt
>> drive between synchronous motor and synchronous generator.  It whined..
>> "Satan's Siren" is what we called it.
>> IBM mainframes used a similar scheme but I can't remember the details.
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