Gary Schafer wrote:
On Wed, 16 Feb 2005 15:00:43 GMT, Larry W4CSC wrote:


Gary Schafer wrote in
m:


And how would you like to be responsible for "telling" them to shut
down the main switch. After doing so there will be a gigantic kick
back of voltage to all the boats tied together on the open ac mains.
The kick back will come from the fields suddenly collapsing in all
those compressors and battery chargers that are on line. Now it is
your fault that someone's equipment got fried! :)

Regards
Gary


Naw....We had all that before the 70V happened. I took the exploded little
surge protector to the marina office and they were very interested in
talking about over and undervoltage sensing equipment. Grangers sells them
for $75. They activate external trip breakers to shut down the marina.
Management was very interested.

Gary, you talk about all this as if the power were some kind of DC circuit.
Any time the power company just shuts the power down, according to your
crazy theories, everything in the grid would be destroyed. We had a huge
overvoltage condition that exploded that surge protector, followed by a
long period of intense brownout. Is brownout better for everyone's
refridgeration than simply shutting the marina down until the power company
can restore the proper voltage?....

I think not.



I suppose you don't know why you should always shut down your air
conditioners on the boat before you disconnect the mains power.

Regards
Gary

No, Gary, we don't. Do you?

There is no difference between shutting off your A/C either at it's
control panel, breaker box, or by shooting up the distribution
transformer down the street. Non. Except for the legalities, of course.

Operating an electric motor on low voltage is more likely to cause
damage by melting from excessive start circuit current.

The reason the power company wants you to turn stuff off in the
event of brown or down power is to reduce the start-up surge they
have to deal with when a million TV's, freezers, and other devices
are all powered up at the same time. The same sort of thing occurs
if you leave your A/C and other stuff turned on and then plug in
shore power. The damage occurs at the connector when small,
incompletely engaged, dirty sliding surface areas get to conduct
heavy starting currents, overheating and possibly damaging your
shore power connector.

Your fear may come from hearing about collapsing fields in DC motor
windings, and it is a real concern when opening and closing
under-rated switches, but not nearly as worrisome as when hydro
tries to kick start millions of home and industrial appliances
simultaneously.

Because customers don't co-operate well, Hydro's systems are
necessarily able to handle large overloads for short periods, all
within reason, of course.

We all need to think about reducing electrical consumption, world
wide. Charity begins at home.

Terry k