365 Main reason for outage report published
deepak at ai.net
Fri Aug 3 18:59:34 UTC 2007
> Register4Less recently reported a power failure in Montreal where the
> return of a single cycle from the utility tricked generators into
> shutting down all three cycles, throwing the data center onto UPS until
> the batteries died. They did not report make of generator or of the
> board that failed them.
Many generator control systems (and transfer switches) do not monitor
all three phases for voltage, and stability (phase sync). Any of these
can cause a UPS to use its batteries (without charging) and not fire up
the generator. Or conversely, allow a generator to power down.
Its happened to lots of people in various places, but I am not going to
More information about the NANOG