Re: Summary: Bay Area Power (2000-06-14)

[John Hall]

When you lose a part of a multi-phase circuit, you usually get bleed
through enduser devices that are still getting power through the other
phases.  Your 27VAC was probably bleen through a (or more likely several)
three-phase motors that did not have phase-outage protection circuit
breakers.  They probably had stopped spinning and were slowly cooking
themselves.  A building I once worked at lost one of their phases and
after an hour the fire alarm went off and we had to evacuate the whole
10 stories.  A "temporary" compressor in a design model shop did'nt have
adequate protection and cooked all it's lubrication, filling the shop
with smoke.  Apparently, phase-outage protection is not required in
many installations where it should be.  One data-center in the same
building still had some three phase powered mini-computers (mini in
name only) and they lost almost half their hardware.

JMH

Jim Browne wrote:
> Downtown Sunnyvale around Carroll Street (including PacBell SNVCA01
> and us) lost power (on one phase only) yesterday at 12:35 PDT.  PG&E
> brought it back at 15:35.  PG&E said that our area is using too much
> power and we blew the breaker on that phase.  The odd thing was we
> were still getting about 27 VAC on that phase with the breaker
> "blown".

-- 
John Hall <j.hall@f5.com>                                     F5 Networks, Inc.
Senior Test Engineer                                          206-505-0800

One of the large consolations for experiencing anything unpleasant is
the knowledge that one can communicate it.
		-- Joyce Carol Oates