[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: any good UPS for a Fedora server



Mikkel L. Ellertson wrote:
John Summerfield wrote:
Mikkel L. Ellertson wrote:
John Summerfield wrote:
In the event of a quake, it seems to me prudent to cut HT and mains, but
then generator sets automatically starting up would tend to negate the
action.

Not really - before you cut the mains, you switch the generator set
control to off instead of auto.
And if the power goes when nobody's home?

The same thing as happens if the power does not go out. Unless your
generator runs out of fuel before the power comes back on. After
all, if nobody is home, you are not going to cut the mains either.

If the mains is down, the power's off.


On the other hand, if you do not want the generator to run while you
are gone, then turn the selector to off as part of the normal
preparation for being gone for 2 weeks. You do do things like turn
off the water heater, put the thermostat in the away setting, and
things of that nature, right?

Being away does not mean I don't want the computers running. I used them daily while away, it's how I knew one didn't come back up.

I was away two weeks recently, and the power went while I was away. One
of the systems didn't come up, and when I got back a week later the
office had an evil smell, the smoke got out of a switch.

About the only change having an auto-start generator would be that
your power would have been out for a shorter period of time,

Without an autostart generator, the system would run for a strictly-limited, short time.

With one, it could run for days.





I fail to see how a properly installed auto-start generator would
increase your risk. The transfer switch isolates the generator from
the outside power - there is never a connection between the
generator and outside power. The only place they should meet is in
the transfer switch, and that is configured so that only one can be
connected to the load at a time, and the two sources can never be
connected to each other. I can see how an improperly connected
generator can cause problems, but that is a problem in any case.


Most power failures are a few seconds, sometimes some electrical appliances don't even seem to notice. Fairly recently, the clock on one oven kept running, the other didn't. Sometimes, some but not all unprotected computers restart.

Once one needs better protection than that, then one increases the time power may be on when it should not.

If it's a UPS protecting a computer or two, it's only covering a small area, it doesn't matter so much, but when you go to backup power supplies powering a house or more (until the 60s we had no mains power, it was all 32-volt DC) then the likelihood increases quite a bit.



--

Cheers
John

-- spambait
1aaaaaaa coco merseine nu  Z1aaaaaaa coco merseine nu
-- Advice
http://webfoot.com/advice/email.top.php
http://www.catb.org/~esr/faqs/smart-questions.html
http://support.microsoft.com/kb/555375

Please do not reply off-list


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]