15 Dec
2004
15 Dec
'04
2:44 a.m.
On Tue, 2004-12-14 at 18:41 -0500, William Donzelli wrote:
We had an electric start Dorman generator at the fortress in NZ (37KW
IIRC) and it'd turn over and start happily in a second or so. I've got
some nice footage somewhere of a power fail test - kill the supply to
the fortress and the lights dim for a couple of seconds whilst the
Dorman kicks in automatically and then everything picks up again.
The pair of British Polar straight-8 diesels up at Palmerston Nrth were
another matter. Each engine's 725 litres in capacity (yep, you read that
right) and have to be barred over prior to starting by hand (it's back-
breaking work). Each engine has a couple of enormous air recievers,
which also need to be charged first and then fire the engine on two
cylinders for starting. The engines run at 300rpm, which gives a
wonderful ground-shaking rumble and thumping noise from the exhaust
stacks.
Output's 3300V three-phase - that'd supply any computer collection
nicely ;-) Not bad for something of 1930's vintage.
Designed for continuous running obviously though, not exactly the sort
of thing you'd want to be stopping and starting all the time :) (takes a
couple of hours start to finish to run through the startup procedure)
cheers
Jules
Reminds me.
The CDC Cyber 960 from http://www.cray-cyber.org/ runs at
400 Hz. The higher frequency allows smaller transformers.
I think the intent was to reduce the ripple, rather than reduce the
weight. CDC wasn't afraid of a few more pounds.
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.
I doubt you could start a big diesel that fast, reliably.