14 Dec
2004
14 Dec
'04
1:08 p.m.
From: "William Donzelli"
<aw288(a)osfn.org>
Hi William
I was right next to a flywheel started no-break diesel.
It was running at full load in about one second from
a complete stand still. My heart was pounding quite hard
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.
The inertia would, however, protect against little dips and burps in the
power, when the utilities are fooling around with the grid.
from the adrenaline rush I got. Another way to start
a diesel fast is with compressed air.
In anycase, "Yes", they can start that fast.
Dwight
14 Dec
14 Dec
1:20 p.m.
I was right next to a flywheel started no-break
diesel.
It was running at full load in about one second from
a complete stand still. My heart was pounding quite hard
from the adrenaline rush I got. Another way to start
a diesel fast is with compressed air.
In anycase, "Yes", they can start that fast.
OK, I suppose you could do something like that. The few big backups I have
seen did not have them, but I could see where they could made that way..
William Donzelli
aw288(a)osfn.org
10:18 p.m.
Dwight K. Elvey wrote:
Hi William
I was right next to a flywheel started no-break diesel.
It was running at full load in about one second from
a complete stand still. My heart was pounding quite hard
from the adrenaline rush I got. Another way to start
a diesel fast is with compressed air.
In anycase, "Yes", they can start that fast.
Dwight
I've seen an industrial diesel genny, eight cylinder two-stroke, barrels
damn near as tall as me. When it's stopped, an electric motor winds it
up to just past TDC on one. To start it there are two compressed air
receivers the size of welding bottles which fire into one then the next
cylinder to pass TDC (can't remember which, probably five). It's kept
warm with a 1kW heater in the oil pan. It's practically capable of full
load before it's finished one complete revolution of the crank...
Gordon.
15 Dec
15 Dec
3:45 a.m.
At 04:08 PM 12/14/04 -0800, you wrote:
My father told me that when he was in the USAF they had generators that
they called Might-Mites. He said that they had a big flywheel and a
motor-generator connected together and a dieal engine connected via a
clutch. Normally it used AC power to drive the motor-generator and flywheel
but when they lost Ac power a relay closed that caused the unit to dump the
clutch and that instantly engaged the engine. The engine went from 0 to
full speed in a fraction of a revolution. It of course started and then
provided power to operate the motor-generator. Those never lost power
because the motor-generator never stopped rotating even during the split
second between the time they lost AC power and the time the engine started.
he said they worked very well. My only comment is that they must have had a
GOOD clutch and a dammed strong crankshaft.
Joe
From: "William Donzelli"
<aw288(a)osfn.org>
Hi William
I was right next to a flywheel started no-break diesel.
It was running at full load in about one second from
a complete stand still. My heart was pounding quite hard
from the adrenaline rush I got. Another way to start
a diesel fast is with compressed air.
In anycase, "Yes", they can start that fast.
Dwight
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.
The inertia would, however, protect against little dips and burps in the
power, when the utilities are fooling around with the grid.
7184
days inactive
7185
days old
3 comments
4 participants
participants (4)
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aw288＠osfn.org -
dwight.elvey＠amd.com -
gordon＠gjcp.net -
rigdonj＠cfl.rr.com