On Fri, 29 Jun 2012 07:46:56 +0100, David WE Roberts wrote:

"D.M.Chapman" dmc@puffin. wrote in message
...
In article , David WE Roberts
wrote:

I've only seen a backup generator kick in once. It was at a computer
centre we were visiting.

Ours kicks in once a month for testing. We pull the feed for the aircon
and lighting to test it kicks in ok.

Once a year we have a full test where we kill power to the datacentre
and let it kick in.

We were just pulling into the car park when all the lights went out,
and there was an enormous bang and a cloud of smoke from round the
back of the
building.

heh, never really noticed that. It does cough a bit when started up but
no loud bang. Does smoke a bit till it's hot though (it's kept
permenantly warm with a heater in the sump but I assume that's more to
keep the oil thinnish). It's amazingly quiet infact given it's a 16l
engine :-)

For a moment we thought that someone had blown up the building, but
then the
lights came up again and we could hear the generator running. Delayed
us for a long time while they restored the systems, though.

Blimey, was that quite a while ago? Most sites that are big enough to
have a gen set will have big (redundant) UPS. We've a bank of n+1
100kVA units.

To have a gen set yet not UPS is odd these days.


Late '70s to early '80s.
ICL main frames which were incredibly sensitive to mains glitches. There
were generally these big MA sets which had massive flywheels and were
used to smooth out the mains, but there wasn't any UPS - presumably
because the power requirements were too large. I still twitch when the
lights flicker because that was the signal to run for the machine room
to estimate the damage from the system crash.

The predecessor to Darren's UPS and genset was a massive MA, which was
kept for quite a while after the ICL mainframe was retired in 1986. I
wouldn't be surprised to see that either batteries or genset are housed
in the same place (I don't know, I stopped working for that cost centre i
1992).

The MA was incredibly reliable, although we paid ICL maintenance for
about 6 years before we realised they'd never actually touched it (or
rather, the contractors, who'd never been informed)! At one point they
came out, dismantled it and replaced the bearings - all within 6 hours;
amazing.



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor