"Watson A.Name - Watt Sun" wrote ...
And some industrial sites (such as the one where I work)
use sophisticated motor-generator sets with dynamic flywheels
to provide truly UNINTERUPPTED standby power even up to
the megawatt level.
We have a couple, each the size of a semi-truck, that run all
the critical computer, network, and production equipment.
They will keep the fab running for several minutes while the
diesel generators fire up.
We had a M-G set back in the '80s for our mainframe. It was a GE, and
sat outside in a lean-to shed against the bldg. It was running at
208V, at about 80 to 90 amps for each of the 3 phases later after we
upgraded and added more disks and mainframe eqpt. The motor was
coupled to the gen with a coupler made from two pieces of steel much
like a universal joint, but instead of bearings, it had a dozen or
more rings of steel, each about the size of a CD, except the hole was
much bigger. One day it started sounding different, so we looked
inside. The steel rings were being thrown out! They had flexed so
many times over the years that they became fatigued and were breaking
up. And at 3600 RPM, they weren't staying put, they were flying out!
So we had to bring down the mainframe one weekend and get the 'field
techs' who were now just grease monekeys to unbolt the half-ton motor
and separate the two and replace the coupler. The hour meter had over
88 thousand hours on it before it froze up and quit working - that's
over ten years.
But it was never satisfactory, since at 80 to 90 amps per phase, the
flywheel wasn't good for many revs before it slowed down and power
dropped - maybe for a half second power outage. Oh yeah, one day it
quit. We took a look in the shed, and we found that the fuse box, the
big one with the ON-OFF switch, had fried. The contacts that clamped
the big fuses on each end had overheated and as usual, got more
oxidized as they heated up, and then fried. So we had to replace the
fuse box.
Another time, we had a power failure and when the power came back on,
the M-G started spinning up, and the power only in the computer room
went off again. So we investigated and found that one of the two big
transformers, only the one feeding the computer room, wasn't humming
outside. Uh-oh. Something major was wrong. We thought at first it
might be a burned out transformer. In any case, it was big-time high
voltage, so the high voltage electricians were called in. They found
that the fuse, not on the 208V secondary, but on the 4KV primary had
blown. This was a 15 amp high voltage fuse, immersed in oil. It
looked like two strands of solder, maybe 3 or 4 inches long, between
some tin strips. We were down for most of the day while the
electrician searched around the county for a supplier that stocked
such a beast. They got a higher current replacement, maybe 20 amps.
Apparently the motor-generator was drawing a whole lotta current
during initial spin-up. Well, what didja expect? It might've been a
25 or 30 HP motor, I forget. The flywheel was made out of heavy
steel, and it doesn't atart instantly either!
So we decided that it was time to upgrade our power supply, and we
disconnected the M-G and put a 80 kW UPS made by Exide in the computer
room. It worked great for another half dozen years until we
demolished the building and moved into our new bldg with a new 150 kW
Exide UPS. We've been sold on the big UPSes ever since, we would
never go back to an M-G set. Outside, we have a huge 300 kW
Caterpillar diesel generator to back up commercial power to the UPS.
5 or so seconds after the power fails, it's revved up and purring,
putting out power. Purring? It's so loud that standing next to it,
even shouting, it's hard to hear a person next to you!
Nowadays they have those super high speed flywheel energy storage
systems that they bury in a pit in the ground. Also there are micro
turbine power generators. From our experience, I doubt that your
flywheel system would store enough energy to run things for several
minutes. Maybe several seconds, tho.
--
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###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it:
http://physics.nist.gov/cuu/Units/binary.html
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