TELECOM Digest OnLine - Sorted: Re: 25 Hz Power

Re: 25 Hz Power

Dale Farmer (
Mon, 13 Mar 2006 01:30:16 GMT

Herb Stein wrote:

> (Thomas D. Horne) "Electrician" <> wrote in message

>> Boston Edison used to provide 600 volt DC service for the operation of
>> elevators and cranes. I don't know if they still do.

> I know Milwaukee, WI had DC available at some point in the distant past. I
> used to have a water cooler with a DC motor from downtown somewhere.

> Upper Michigan had 25Hz (cycles/second at the time) at a number of
> copper mining operations, if memory serves.

>> Tom Horne

>> "This alternating current stuff is just a fad. It is much too dangerous
>> for general use." Thomas Alva Edison

> Herb Stein

> [TELECOM Digest Editor's Note: A water cooler with a DC motor is
> interesting; but did you ever see a _refrigerator_ powered by -gas-
> rather than -electricity-? I had one of those in a long since for-
> gotten apartment in Chicago back in the 1960's. No motor of course, no
> compressor, etc, but it was a refrigerator, freezer, etc, and I think
> (cannot remember for sure) it was manufactured by 'Frigidaire
> Company'. Totally silent of course. I have no idea how it worked; if
> I ever knew, I have since forgotten. PAT]

Usually ammonia absorption cycle. Commonly found in motor homes and
places that don't have electricity, such as remote vacation/hunting
cabins, or small islands. Google for RV refrigerators to find lots of
sites that explain them better than I can. Only moving parts are the
gas valve and thermostat.

Although this brings to mind a telecom subject. How can you get
telephone service out to places small islands that have residents who
want phone service? These sorts of places are usually not that large,
having anywhere from one to a few hundred residents, so not lots of
income potential there. Nowadays they probably just have cell phones,
if they have coverage.


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