As of today, you no longer get a choice:
"[NEW YORK] Today, Con Edison will end 125 years of direct current
electricity service that began when Thomas Edison opened his Pearl Street
power station on Sept. 4, 1882. Con Ed will now only provide alternating
Next thing you know, Con Ed will be upgrading to Windows 3.1.
When I was a kid, Boston Ed was still supplying DC to the area where I
It was truly a pain in the ass.
For instance, when you plugged in an ac/dc radio the odds were 50-50 the
polarity was wrong.
Try to shut of a light and sometimes there would be an arc across the switch
gap and you had to unsscrew the bulb to get the circuit to break and get
thearc to extinguish.
Plug in a new electric iron with temperature control and when the thermostat
tried to open the contacts would weld together. Toasters too.
Want one of those TVs towatch Friday night fights. You had to get a
converter that had DC in and gave you AC out. Or if you had bigger bucks,
you could buy a motor/genrator set.
Yeah. those were the good old days.
When I was a kid, the province of Ontario, had 25 hertz AC electricity.
Motors turned much slower and were larger, and light bulbs flickered. The
power was gradually transferred over to North American standard 60 hertz in
the 50's. The city of Toronto, being the largest was done last. Virtually
every motor, transformer and other equipment had to be replaced, exchanged
or rebuilt at that time.
Wow...that's interesting. Much of Los Angeles was 50 Hz until well after
Much of Amtrak's Northeast Corridor electrification (former Pennsylvania
and New Haven railroads) is still 25 Hz and probably will remain so. A
couple decades back it was expected that it would be converted to 60 Hz
(some of it did convert and the new electrification from New Haven to
Boston is 60) but most of it remains 25. Apparently, even though there are
no longer locomotives and cars that use the AC commutator traction motors
(it's all either rectifers & DC motors or rectifier -> variable frequency
inverter -> 3-phase AC induction motor) there are certain advantages to 25
Hz. Not enough to install new but enough to keep it if you have it.
They've been changing rotary converters to static (electronic) ones. Even
that has its drawbacks. I remember reading a technical paper that touted
the virtues of modern rotary converters.
In Europe a lot of railway electrification is 16 2/3 Hz.
I'm really curious about a reference I have seen to Con Ed still generating
DC up til about 1985. I can see how they still were supplying it but I
would have assumed that just meant a transformer / rectifier setup in the
nearest substation. But to actually generate DC? I wonder if that's true.
Me too, when I rented a one room student apartment in the Back Bay
section of Boston circa 1956.
I never thought to ask about the current supply in the building and soon
discovered the place was still on DC.
I was a "hi-fi" buff back then and after I considered what a PIA it
would be to have to use one of the vibrator converters available back
then, I just suffered for a month and then moved elsewhere.
Thanks for the mammaries!
I used to work with an electrician years ago who had worked on converting
Columbia University over from DC to AC. Before that I had no idea that DC
was still in use.
That's strange because there is now research about supplying DC to large
computer centers because it would save money in switching power supply losses
and the accompanying heat loads they impose...
Tekkie Don\'t bother to thank me, I do this as a public service.
I wish I had 12VDC distributed throughout my house. Then I could get
rid of all those ugly wall wart AC->DC convertors.
... Never liked being surrounded by low-frequency magnetic fields
anyway. Edison was right... DC is better. Down with reactance!!!
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