VAXen at home

[Jules Richardson]

Jochen Kunz wrote:
> On Tue, 16 Oct 2007 21:49:44 +0100
> Jules Richardson <julesrichardsonuk at yahoo.co.uk> wrote:
> 
>> That's the sort of thing worthy of video. Big power control stuff is
>> fun :)
> You can visit it: http://www.cray-cyber.org/

Rats, seems to be broken at the moment (I get a connection, but no data ever 
comes back) :-(

>> Was that rating for the entire system, or just the CPU & I/O (no
>> drives etc.)?
> It was just the MG starting. The machine was switched off. Current
> droped to a few A once the MG got to speed. The MG has a big flywheel.
> Therefore it needs all that energy to get up to speed. The idea is that
> the flywheel stores enough energy to compensate short power outages. If
> power stays off longer the disel kicks in. (But at Cray-Cyber they
> skiped the disel. ENOSPACE.) AFAIK a minimal configuration of the
> machine (CPU + I/O) needs about 20 kW.

Ahh, I think we're talking about different things. To me, a motor-generator is 
a diesel (or other non-electric power source) driving a generator to produce 
electricity; I've always known something which just converts electric between 
forms as a rotary converter. (but I'm not sure quite what I'd call a 
flywheel-storage device)

Maybe the terms are ambiguous... or I'm just plain wrong ;-) (I've had a few 
experiences with generating plant, but not in a computer context...)