From time to time I've wondered why the standard US lighting voltage
was (when I was a kid) 110 volts and not a "rounder" number like 100 or
maybe 150.

I think I may have located a believable answer, purportedly in Edison's
own words, on page 66 of this document, under the heading "Why 110 Volts":

http://www.ias.ac.in/resonance/Jan20...2000p60-70.pdf

Now, can someone tell me when and why it was "increased" to 115 and then
120 volts? Will I live to see it become 125 volts in a few years? G

Jeff

(Next, why did the early phonograph records revolve at 78 RPM? and have
you ever wondered why 33 and 45 add up to 78?)

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.98*10^14 fathoms per fortnight.

Jeff Wisnia wrote:
From time to time I've wondered why the standard US lighting voltage
was (when I was a kid) 110 volts and not a "rounder" number like 100 or
maybe 150.

....
... Will I live to see it become 125 volts in a few years? G
....

Heck, I see anywhere from 123 to 130 now! (Although it usually seems
closer to 127)

In article , Jeff Wisnia wrote:

(Next, why did the early phonograph records revolve at 78 RPM? and have
you ever wondered why 33 and 45 add up to 78?)


"Earliest rotation speeds varied widely, but between 1900-1925 most records
were recorded between 74-82 rpm. In 1925, 78.26 rpm was chosen as the standard
because of the introduction of the electrically powered synchronous turntable
motor. This motor ran at 3600 rpm with a 46:1 gear ratio which produced 78.26
rpm. In parts of the world that used 50 Hz current, the standard was 77.92
RPM ..."
http://en.wikipedia.org/wiki/Gramophone_record#Speeds

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

higher voltage reduces current a little too.....

euope uses higher voltage to keep conductors smaller, and remember the
power to your home gets converted many times by transformers before
arriving at your socket. low voltage can cause big grief so the keep
raising it over ime

wrote:
higher voltage reduces current a little too.....

euope uses higher voltage to keep conductors smaller, and remember the
power to your home gets converted many times by transformers before
arriving at your socket. low voltage can cause big grief so the keep
raising it over ime

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

In article , Stubby wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on the
continent?

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Doug Miller wrote:

In article , Stubby wrote:


True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.


Who's going to pay for replacing every alternating-current motor on the
continent?


Plus I'd bet that the significantly higher capacitive currents between
conductors would waste a huge amount of power in resistive losses.

IIRC 400Hz power was used in aircraft circa WWII, I lost track of
whether it's still a standard there.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

On Wed, 10 Jan 2007 09:49:51 -0500, Stubby
wrote:

wrote:
higher voltage reduces current a little too.....

euope uses higher voltage to keep conductors smaller, and remember the
power to your home gets converted many times by transformers before
arriving at your socket. low voltage can cause big grief so the keep
raising it over ime

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

The frequency used also depends on the limits of rotating machinery
(generators and motors). This decision was made before inexpensive
power electronics made high frequency reasonable.
--
Mark Lloyd
http://notstupid.laughingsquid.com

"Properly read, the Bible is the most potent
force for atheism ever conceived." -- Isaac Asimov

In article , (Doug Miller) wrote:
In article , Stubby
wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on the
continent?

And how much energy would be consumed in the process of making
the conversion?

--
|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~|
| Malcolm Hoar "The more I practice, the luckier I get". |
| Gary Player. |
| http://www.malch.com/ Shpx gur PQN. |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~

Jeff Wisnia spake thus:

Doug Miller wrote:

In article , Stubby
wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on
the continent?

Plus I'd bet that the significantly higher capacitive currents between
conductors would waste a huge amount of power in resistive losses.

IIRC 400Hz power was used in aircraft circa WWII, I lost track of
whether it's still a standard there.

I think 400 Hz or thereabouts is used in some electric rail transit
systems (like BART).


--
Just as McDonald's is where you go when you're hungry but don't really
care about the quality of your food, Wikipedia is where you go when
you're curious but don't really care about the quality of your knowledge.

- Matthew White's WikiWatch (http://users.erols.com/mwhite28/wikiwoo.htm)

In article m,
kens says...
Jeff Wisnia spake thus:

Doug Miller wrote:

In article , Stubby
wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on
the continent?

Plus I'd bet that the significantly higher capacitive currents between
conductors would waste a huge amount of power in resistive losses.

IIRC 400Hz power was used in aircraft circa WWII, I lost track of
whether it's still a standard there.

I think 400 Hz or thereabouts is used in some electric rail transit
systems (like BART).

From what I can tell, most US systems are 60Hz since they can buy
standard equipment. Some older systems are strange for historical
reasons (generation equipment). I believe the NYC subway system is
25Hz, or some such. I'd be very surprised if any used 400Hz since
saving weight isn't as important as reducing losses.

--
Keith

In , krw wrote in part:

From what I can tell, most US systems are 60Hz since they can buy
standard equipment. Some older systems are strange for historical
reasons (generation equipment). I believe the NYC subway system is
25Hz, or some such. I'd be very surprised if any used 400Hz since
saving weight isn't as important as reducing losses.

If a transformer designed for 60 Hz is operated at 400 Hz, losses would
be less than at 60 Hz, although output voltage with a heavy load may droop
if not much work went into reducing leakage inductance. 400 Hz
transformers at 400 Hz also normally have less losses than 60 Hz ones of
same volt/amp ratings being operated at 60 Hz. And a 400 Hz transformer
would cost less to make than a 60 Hz one of the same ratings, since it
would be smaller and use fewer turns of wire.

The way I heard it, a lower frequency was preferred for motors and
that's why 60 Hz was chosen. Also, 400 Hz could be high enough for wire
inductance to be a problem with longer distance transmission lines, but I
don't know how badly or if transmission line inductance affected 60 Hz
being chosen for our main AC power frequency.

- Don Klipstein )

In article ,
says...
In , krw wrote in part:

From what I can tell, most US systems are 60Hz since they can buy
standard equipment. Some older systems are strange for historical
reasons (generation equipment). I believe the NYC subway system is
25Hz, or some such. I'd be very surprised if any used 400Hz since
saving weight isn't as important as reducing losses.

If a transformer designed for 60 Hz is operated at 400 Hz, losses would
be less than at 60 Hz, although output voltage with a heavy load may droop
if not much work went into reducing leakage inductance. 400 Hz
transformers at 400 Hz also normally have less losses than 60 Hz ones of
same volt/amp ratings being operated at 60 Hz. And a 400 Hz transformer
would cost less to make than a 60 Hz one of the same ratings, since it
would be smaller and use fewer turns of wire.

It's not an issue of transformer losses, rather distribution
losses.

The way I heard it, a lower frequency was preferred for motors and
that's why 60 Hz was chosen.

FOr the AUS distribution system? AFAIK, 60Hz was chosen because it
was a good tradeoff of several variables (transformer cost, losses,
generation ease, and likely a dozen other considerations). As far
as locomotion, I believe 60Hz is rather recent and used because the
equipment is off-the-shelf. Most older subway and commuter systems
are in the 25Hz range. I highly doubt modern DE engines are 60Hz.
;-)

Also, 400 Hz could be high enough for wire inductance

Capacitance?

to be a problem with longer distance transmission lines, but I
don't know how badly or if transmission line inductance affected 60 Hz
being chosen for our main AC power frequency.

I do believe it was one of the factors in the selection. Flicker
could be the reason that it went no lower too. Dunno.

--
Keith

krw spake thus:

In article m,
kens says...

Jeff Wisnia spake thus:

Doug Miller wrote:

In article , Stubby
wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on
the continent?

Plus I'd bet that the significantly higher capacitive currents between
conductors would waste a huge amount of power in resistive losses.

IIRC 400Hz power was used in aircraft circa WWII, I lost track of
whether it's still a standard there.

I think 400 Hz or thereabouts is used in some electric rail transit
systems (like BART).

From what I can tell, most US systems are 60Hz since they can buy
standard equipment. Some older systems are strange for historical
reasons (generation equipment). I believe the NYC subway system is
25Hz, or some such. I'd be very surprised if any used 400Hz since
saving weight isn't as important as reducing losses.

Actually, it turns out that BART is 1,000 volts DC:
http://www.bart.gov/about/history/systemfacts.asp


--
Just as McDonald's is where you go when you're hungry but don't really
care about the quality of your food, Wikipedia is where you go when
you're curious but don't really care about the quality of your knowledge.

- Matthew White's WikiWatch (http://users.erols.com/mwhite28/wikiwoo.htm)

David Nebenzahl spake thus:

krw spake thus:

In article m,
kens says...

Jeff Wisnia spake thus:

Doug Miller wrote:

In article , Stubby
wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes
for bigger transformers. If we were serious about saving, we'd
increase the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on
the continent?

Plus I'd bet that the significantly higher capacitive currents
between conductors would waste a huge amount of power in resistive
losses.

IIRC 400Hz power was used in aircraft circa WWII, I lost track of
whether it's still a standard there.

I think 400 Hz or thereabouts is used in some electric rail transit
systems (like BART).

From what I can tell, most US systems are 60Hz since they can buy
standard equipment. Some older systems are strange for historical
reasons (generation equipment). I believe the NYC subway system is
25Hz, or some such. I'd be very surprised if any used 400Hz since
saving weight isn't as important as reducing losses.

Actually, it turns out that BART is 1,000 volts DC:
http://www.bart.gov/about/history/systemfacts.asp

Turns out the Apollo Lunar Module used 400 Hz power (that is, if
Wikipedia is to be believed):
http://en.wikipedia.org/wiki/Apollo_Lunar_Module

And the Monterey Bay Aquarium Research Institute's underwater ROV
(Remotely Operated Vehicle) runs on 400 Hz:
http://www.mbari.org/staff/meed/powerpaper/pwrpaper.htm

Lots of others if you google for "propulsion system" "400 hz" (with the
quotes).


--
Just as McDonald's is where you go when you're hungry but don't really
care about the quality of your food, Wikipedia is where you go when
you're curious but don't really care about the quality of your knowledge.

- Matthew White's WikiWatch (http://users.erols.com/mwhite28/wikiwoo.htm)

Large aircraft ( like jetliners) are generally 400 Hz, 115/200 volts 3 phase
ac , some smaller ones have 28 volt dc systems.
The 400 Hz power is supplied on the ground either by engine driven
alternators or by converters, they used to be large motor/generator sets
but these have mostly been replaced by solid state converters, which are
smaller, lighter and more efficient especially at low loads, though not so
reliable as the old MG sets.

--

Mike S.

"David Nebenzahl" wrote in message
s.com...

Turns out the Apollo Lunar Module used 400 Hz power (that is, if Wikipedia
is to be believed): http://en.wikipedia.org/wiki/Apollo_Lunar_Module

And the Monterey Bay Aquarium Research Institute's underwater ROV
(Remotely Operated Vehicle) runs on 400 Hz:
http://www.mbari.org/staff/meed/powerpaper/pwrpaper.htm

Lots of others if you google for "propulsion system" "400 hz" (with the
quotes).

NYC Subway systems are 600 Volts DC
krw wrote:
In article m,
kens says...
Jeff Wisnia spake thus:

Doug Miller wrote:

In article , Stubby
wrote:

True, but they use 50 Hz rather that 60 Hz in the US. That makes for
bigger transformers. If we were serious about saving, we'd increase
the frequency to about 10,000 Hz.

Who's going to pay for replacing every alternating-current motor on
the continent?

Plus I'd bet that the significantly higher capacitive currents between
conductors would waste a huge amount of power in resistive losses.

IIRC 400Hz power was used in aircraft circa WWII, I lost track of
whether it's still a standard there.

I think 400 Hz or thereabouts is used in some electric rail transit
systems (like BART).

From what I can tell, most US systems are 60Hz since they can buy
standard equipment. Some older systems are strange for historical
reasons (generation equipment). I believe the NYC subway system is
25Hz, or some such. I'd be very surprised if any used 400Hz since
saving weight isn't as important as reducing losses.

--
Keith

Mikey S. wrote:
Large aircraft ( like jetliners) are generally 400 Hz, 115/200 volts 3 phase
ac , some smaller ones have 28 volt dc systems.
The 400 Hz power is supplied on the ground either by engine driven
alternators or by converters, they used to be large motor/generator sets
but these have mostly been replaced by solid state converters, which are
smaller, lighter and more efficient especially at low loads, though not so
reliable as the old MG sets.

Primary reason for going to 400 Hz is that the instrumentation devices
such as synchros and resolvers could be much smaller. There are some up
to 1600 Hz.

JGolan wrote:
NYC Subway systems are 600 Volts DC
krw wrote:

this permitted easy speed control dc motors are variable speed by
nature, the high voltage keeps the conductor sizes down......