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.

Darren