----- Original Message -----
From: "Richard L. Hess" <[log in to unmask]>
> >Italian electric railroads used 14 Hz, because the motors used switches
> >could function at that "high" frequency.
> Interesting...I never knew that!
> >As to length of AC power lines: the grid going from the north of Sweden
> >the South of Denmark once got into wild oscillations - a huge standing
> >We, too, and the Russians, use AC-DC conversion at convenient points.
> Yes, I didn't mean to imply it was a U.S. invention. In fact, the
> undisputed world leader in this is a Swedish corporation (although it is
> now Swedish Swiss since 1988). Asea Brown Bovari.
> Here is an interesting link to their DC business:
> I didn't do a lot of research, but the new Three Gorges project in China
> using ABB DC transmission.
> We have two DC lines coming into LA, one from the Columbia River and the
> other from the Hoover Dam on the Colorado River.
> Vancouver Island gets its power over a DC link to the mainland.
> There is a DC tie between the North and South islands of NZ...
> Fascinating stuff. If you're interested in this, be prepared to spend a
> couple of hours on the ABB site. I did a couple of years ago and am
> resisting going back right now.
I can very dimly recall (probably early 1950's) when hotels sometimes had
their own DC generators. I would suppose other places did as well, which
would explain the popularity of AC-DC radios long after DC power was
Were the 32-volt farm power plants DC? I would suppose they were, and
used a battery-based system similar to automobiles? You can occasionally
run across 32-volt farm radios...
Steven C. Barr