TELECOM Digest OnLine - Sorted: Re: Gas Refrigerator (was 25 Hz Power)

Re: Gas Refrigerator (was 25 Hz Power)
17 Mar 2006 11:01:57 -0800

T wrote:

> Unfortunately for me I've never heard a live electromechanical
> switch.

Telephone switches have a distinctive sound. The clicks and clacks are
very sharp and distinctive.

While an ESS switch is silent (except for the noisy blowers), there
may be some nearby support racks that do contain relays, and those
relays will make the sharp clack sounds.

As to the sound of emergency generators, they are noisy. I was
passing a nursing home when they were testing their generator and it
was loud!

Places with critical functions likes hospitals and nursing homes have
backup power generators. They are tested every so often. Sometimes
power failures result from failure of the switchgear to transition
from one source to another. One of my employer's location had a
backup source and they did a test; they were out of commission the
whole day due to failures of the control circuitry.

Electric power control circuitry is pretty amazing to me. It must
handle -- live -- tremendous amounts of current.

The power system today is pretty fancy and duplicated which means
power failures are quiten uncommon even when one piece gets hit by
lightning. Unfortunately, it is so interconnected that a bad failure
will ripple and make a big mess. It happened in 1965 causing the big
NE blackout and again not too long ago causing another NE blackout.

Unfortunately, once large segments go out, it takes a while to bring
them all back online; they can't flip a switch and do a whole city at
once. Also, once a power plant itself goes off line, it takes a while
to build back up.

I wish there was some cost-efficient practical manner of "buffering"
large amounts of power for brief moments to avoid huge surges that
cause everything to shut down. If the safety breakers are too
sensitive there will be too many false trips causing unnecessary
problems. If the breakers aren't sensitive enough surges will ripple

The 1965 NE power failure has been documented as to causes and
solutions (which presumably have been implemented). But I don't know
if they ever published the analysis of the more recent NE power
failure. I believe it was caused by surges in an Ohio system that
rippled to other systems. I don't know if there is a protection
against such "rippling". That's why I wish there were some kind of

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