electro-Physics: 17.3409 volts

From: Jochen Kunz <jkunz_at_unixag-kl.fh-kl.de>
Date: Tue Dec 14 16:32:05 2004

On Tue, 14 Dec 2004 19:42:16 +0100
Tore S Bekkedal <toresbe_at_ifi.uio.no> wrote:

> > For not-so-heavy transformers, higher frequencies are desirable,
> > thus the 400 Hz AC power on military aircraft.
> > The classic way of converting from AC at one frequency to another
> > was motor-generator sets, (And to convert AC to DC you used rotary
> > converters...) Modern implemenations use solid-state electronics.
> Twisting this back on topic, the IBM 650 had a power distribution that
> made something like 133Hz AC or even higher.
Reminds me. The CDC Cyber 960 from http://www.cray-cyber.org/ runs at
400 Hz. The higher frequency allows smaller transformers. As this is
three phase you can get DC quite easy and efficient with a six pulse
rectifier. I was toled that the PSUs have no regulation. The machine is
build from ECL. ECL has a constant current consumtion, in oposite to TTL
or CMOS. So all you need for a PSU is a six pulse rectifier and a
smoothing capacitor. The voltage drop caused by the PSU load is
compensated by a slightly higher PSU output voltage. Simple, efficient
and elegant.

The 400 Hz three phase current is generated by a motor-generator. The
rotating mass of this machine is enough to keep the Cyber running for
some seconds. (Power consumption of the Cyber at minimal configuration
is around 20 kW.) Enough to start a big diesel generator in case of a
power outage. (They don't have a diesel at the cray-cyber basement, but
it was usual at "regular" installations.)
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/
Received on Tue Dec 14 2004 - 16:32:05 GMT

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