Re: SEMI off topic
- From: stevet@xxxxxxxxxx (Steve Thompson)
- Date: 8 Jan 2008 19:12:59 -0800
On Tue, 8 Jan 2008 20:24:49 -0600, Ed Gould <edgould1948@xxxxxxxxxxx> wrote:
This is not specifically MAINFRAME question But I ran across this<SNIP>
article that talks about replacing their UPS with a fly wheel system
(please read the article) at >http://searchdatacenter.techtarget.com/
originalContent/0,289142,sid80_gci1288892,00.html?
track=NL-455&ad=619599&asrc=EM_NLN_2844322&uid=6570353<
Watch the wrap above
My problem with this way of doing UPS is that the article states that
they can loose power a full second before the "new" UPS kicks in.
I don't think the person that wrote that article was really up to speed on
how this works.
Many years ago I was taken to a TELCO site where this was done. Mind you,
the TELCO ran a bank of batteries to run the phone system (this was just as
touch tone was being introduced). But the batteries were between the phone
system and the generator. The generator was turned by a large electric
motor. That motor was connected to a large flywheel that was connected to a
large diesel engine by an electrically controlled clutch.
The inertia of the motor, flywheel and generator where such that when the
capacitors ran down (which happened when there was a drop in external
power), that diesel engine would go from 0RPM to 600+RPM in about 1/4
rotation (shook the floor when that happened!). And I happened to be there
when it was triggered by a power glitch - that's how I know about the floor.
Now as I understood at the time, that whole system was set up to take over
if the external power dropped for about 1 second and run for 30 minutes past
the last "missing" beat from the external AC power.
And the ammeters at the end of the battery bank (about 24 feet long and four
12v batteries wide) hardly flickered.
That was about 1964. Given the changes in technology in the past 40+ years,
I would imagine that a flywheel spun up to 54,000 RPM (as the secondary
article specified) should hold up for a few seconds anyhow, before some
engine-generator system would have to kick in. Again, it would depend on the
power requirements. But I would imagine it would be cheaper in the long run
than the typical bank of batteries to drive a UPS.
Later,
Steve Thompson
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