Tom Marchant wrote:
On Wed, 9 Jan 2008 09:36:22 -0000, Phil Payne wrote:
... every machine was powered via motor-generators.
For those of you who might not know what that was or why, the processors of
that time generally specified 415 Hz three phase power to operate them.
<snip>
True at the high end only. e.g., 168s used MGs because they used 415Hz
power but 158s did not; they just used regular old 3-phase 60Hz 220V power.
I never did know why, though. I always wondered whether it was to keep
the number and size of power supply capacitors to a reasonable minimum.
--
John Eells
z/OS Technical Marketing
IBM Poughkeepsie
[EMAIL PROTECTED]
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