I think you'll find that to be an interesting topic.  There is
a lot more than one might think that went on in the early part of the
twentieth century and latter part of the nineteenth.

        A number of cities in the East did use DC and continued to do
so for several years in to the twentieth century.  I remember a test
record that was shipped with Talking Book machines in the early
sixties that warned people not to plug their Talking Book machine in
to a DC outlet.  Apparently, you could do that in some places.  Just
think, back in the early part of the twentieth century, most of the
things people used that were electrically powered were electric lights
and heaters, all of which would run just as well on DC as AC.

        Old AM radios that used the common 4-tubes and a rectifier
design would work just fine on DC as long as you had the plug facing
the correct direction in the outlet.  If it was wrong, the tubes would
light up, but you wouldn't hear any sound.

        Brush-type electric motors that use a field excited by the
power are called universal motors and will run on both DC or AC but
usually run better on DC.  The thing is that they would have worked on
either AC or DC.

        In the Niagra Falls area, the AC was 25 Hertz at first.  Very
big electric motors work well at this low frequency.  I think the New
York City Subway used and may still use that frequency for motors.

        Southern California used to use 50 Hertz power until sometime
around 1930 or so.

        I ran across a web site for the Pasadena Power and Water
Department in which they gave a brief history.  It seems as though in
1906, they had a mixture of 50 and 60 Hertz.  The power station was
originally first used for street lighting so it powered up at Sundown
and ran until daybreak at which time it was shut down until the next
evening.

        The Hoover Dam was originally designed for 50 Hertz operation
but the engineers decided they could safely just run the water wheels
faster to produce 60-HZ AC in order to standardize.

        I live in Oklahoma which was Indian Teri tory until it became a
state in 1907.  The power history here is not nearly as varied as it
is on the East and West Coasts because by the time people of European
decent begin building cities here, the US was moving towards 60 Hertz
as the standard line frequency.

        I heard rumors that Oklahoma Gas and Electric had DC service
to buildings in down-town Oklahoma City for industrial purposes, but
as far as I know, most towns here have always been 120-volt 60 HZ for
the primary service.  Of course, the distribution system has gotten
beefier as demand increases, but that is true everywhere.

        I once got to examine an electric meter built in 1910.  It was
a baby version of the same construction that modern electric meters
have.  The only difference was that the 1910 meter only had one phase.
No 220-volt service yet.  I think it also may have had one less hand
because people just didn't use nearly the amount of electricity then
that they use now.  Otherwise, the design is the same as most
watt-hour meters today.

Martin McCormick WB5AGZ  Stillwater, OK
OSU Information Technology Division Network Operations Group