J
Jim Hawkins
Guest
Is a mains transformer designed for 60Hz significantly lighter than one of
the same VA rating designed for 50Hz ?
Jim Hawkins
the same VA rating designed for 50Hz ?
Jim Hawkins
P
PeterD
Guest
On 1/16/2012 10:40 AM, Jim Hawkins wrote:
--
I'm never going to grow up.
Significantly? No... One for 400 Hz would however.
--
I'm never going to grow up.
K
krw@att.bizzzzzzzzzzzz
Guest
On Mon, 16 Jan 2012 15:40:41 -0000, "Jim Hawkins" <jimhawkins@manx.net> wrote:
About 20%. Is that significant?
J
Jamie
Guest
Jim Hawkins wrote:
But you must remember that many places where 50Hz
is used, the voltages are a little different so one
transformer could conceivably be used for both. It
most likely wouldn't pass a local ordinance rule due
to a name plate not agreeing.
For example, not to long ago I approved a motor to be
used in a 480 60hz application where the name plate was
as a ~400 v 50hz unit.
End results was the same, with the exception of a little higher
RPM than marked on the ID of course.
Just think V/hz ratio.
Jamie
~ 17% lighter.
But you must remember that many places where 50Hz
is used, the voltages are a little different so one
transformer could conceivably be used for both. It
most likely wouldn't pass a local ordinance rule due
to a name plate not agreeing.
For example, not to long ago I approved a motor to be
used in a 480 60hz application where the name plate was
as a ~400 v 50hz unit.
End results was the same, with the exception of a little higher
RPM than marked on the ID of course.
Just think V/hz ratio.
Jamie
P
PeterD
Guest
On 1/16/2012 7:37 PM, Jamie wrote:
50/60 hz, too. The dual rating means that there is one less item that
they have to manage in the inventory and manufacturing process.
--
I'm never going to grow up.
It is also not uncommon for smaller power transformers to be rated as
50/60 hz, too. The dual rating means that there is one less item that
they have to manage in the inventory and manufacturing process.
--
I'm never going to grow up.
J
Jim Hawkins
Guest
Jim Hawkins wrote:
such low frequencies as 50 or 60 Hz ?
As the frequency rises, the energy lost through electromagnetic radiation
from the wires rises, but is it really a significant amount ? Would it be
significant at 1 kHz ? If not, why isn't generation done at that sort of
frequency ? The savings in transformer weights and sizes everywhere would
be enormous. Is it because of mechanical engineering limitations on the
rotational speeds of the large rotary generators the power stations use ?
Following on from this, why is it that electricity generation is limited to
such low frequencies as 50 or 60 Hz ?
As the frequency rises, the energy lost through electromagnetic radiation
from the wires rises, but is it really a significant amount ? Would it be
significant at 1 kHz ? If not, why isn't generation done at that sort of
frequency ? The savings in transformer weights and sizes everywhere would
be enormous. Is it because of mechanical engineering limitations on the
rotational speeds of the large rotary generators the power stations use ?
K
krw@att.bizzzzzzzzzzzz
Guest
On Sat, 21 Jan 2012 14:51:55 -0000, "Jim Hawkins" <jimhawkins@manx.net> wrote:
generator of a useful size (60Hz = 3600RPM, much better). Multipole
generators are possible, but that only reduces this linearly and increases the
size similarly.
Losses. Mechanics.
Yes.
Yes, certainly.
Partly. 1kHz translates to a 60,000 RPM generator. That's kinda high for a
generator of a useful size (60Hz = 3600RPM, much better). Multipole
generators are possible, but that only reduces this linearly and increases the
size similarly.
T
tm
Guest
<krw@att.bizzzzzzzzzzzz> wrote in message
news:rhnlh7pbb5rpbb6qr1qe8o7vphb73khim5@4ax.com...
news:rhnlh7pbb5rpbb6qr1qe8o7vphb73khim5@4ax.com...
Instead of hum, you would have whine.
K
krw@att.bizzzzzzzzzzzz
Guest
On Sat, 21 Jan 2012 11:10:06 -0500, "tm" <No_one_home@white-house.gov> wrote:
Good point. Perhaps it should be 20kHz. ;-)
T
tm
Guest
<krw@att.bizzzzzzzzzzzz> wrote in message
news:v9rlh75ksbe5uvhkuuncd5l0b8mev0iihg@4ax.com...
department grant.
news:v9rlh75ksbe5uvhkuuncd5l0b8mev0iihg@4ax.com...
Hmmm, waveguide at 133kv. Sounds like that would qualify for an energy
department grant.
U
Uwe Hercksen
Guest
Jim Hawkins schrieb:
400 Hz is used for electric power distribution in airplanes, but if we
would use this frequency for terrestic distribution, problems with
transmission line effects would be much worse. If an AC generator would
feed a distribution line with the length of a quarter wavelength, the
voltage at the other end would rise infinitly. This is called Ferranti
effect:
http://en.wikipedia.org/wiki/Ferranti_effect
Bye
Hello,
400 Hz is used for electric power distribution in airplanes, but if we
would use this frequency for terrestic distribution, problems with
transmission line effects would be much worse. If an AC generator would
feed a distribution line with the length of a quarter wavelength, the
voltage at the other end would rise infinitly. This is called Ferranti
effect:
http://en.wikipedia.org/wiki/Ferranti_effect
Bye
M
Michael A. Terrell
Guest
tm wrote:
Like a lot of Usenet posts. ;-)
--
You can't have a sense of humor, if you have no sense.
Like a lot of Usenet posts. ;-)
--
You can't have a sense of humor, if you have no sense.
T
tm
Guest
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:7tmdnY45-5R9BLzSnZ2dnUVZ_oOdnZ2d@earthlink.com...
Regards, etc.
news:7tmdnY45-5R9BLzSnZ2dnUVZ_oOdnZ2d@earthlink.com...
Ha. I have a sticker on my helmet that says "Stop Global Whining".
Regards, etc.
S
Sjouke Burry
Guest
"Jim Hawkins" <jimhawkins@manx.net> wrote in
news:uZ6dnX1KQIiQTIfSnZ2dnUVZ8nCdnZ2d@supernews.com:
on(or under) the ground.
You could hear the 3rth harmonic(1200 Hz) all over the
place, wich is not such a good idea in your home.
Very iritating for new workers, old workers had a
measurable dip in their hearing curve, and could not
hear that frequency anymore.Permanent damage.
news:uZ6dnX1KQIiQTIfSnZ2dnUVZ8nCdnZ2d@supernews.com:
I have worked in the airforce, they also used 400 Hz
on(or under) the ground.
You could hear the 3rth harmonic(1200 Hz) all over the
place, wich is not such a good idea in your home.
Very iritating for new workers, old workers had a
measurable dip in their hearing curve, and could not
hear that frequency anymore.Permanent damage.
F
Fred Abse
Guest
On Sat, 21 Jan 2012 10:53:11 -0500, krw@att.bizzzzzzzzzzzz wrote:
https://secure.wikimedia.org/wikipedia/en/wiki/Alexanderson_alternator
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
https://secure.wikimedia.org/wikipedia/en/wiki/Alexanderson_alternator
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
P
PeterD
Guest
On 1/27/2012 12:42 PM, Fred Abse wrote:
frequency are not related, the speed and the number of poles in a
generator head determine the frequency. Most 400 Hz generator sets run
at 2000 RPM. Your flawed concept would have them running at 24K RPM!
--
I'm never going to grow up.
Huh? Where does anyone say 1kHz translates to a 60K RPM? The speed and
frequency are not related, the speed and the number of poles in a
generator head determine the frequency. Most 400 Hz generator sets run
at 2000 RPM. Your flawed concept would have them running at 24K RPM!
--
I'm never going to grow up.
M
Michael A. Terrell
Guest
PeterD wrote:
Now you've gone and done it! Very few people remember that
Alexanderson Alternators were used as very early keyed transmitters,
when 'Spark was king!' They have never seen anything like
Alexanderson's designs, and the concept isn't covered in any book on
motors I've ever seen. I learned about them, years ago while studying
early radio.
--
You can't have a sense of humor, if you have no sense.
Now you've gone and done it! Very few people remember that
Alexanderson Alternators were used as very early keyed transmitters,
when 'Spark was king!' They have never seen anything like
Alexanderson's designs, and the concept isn't covered in any book on
motors I've ever seen. I learned about them, years ago while studying
early radio.
--
You can't have a sense of humor, if you have no sense.
F
Fred Abse
Guest
On Sat, 28 Jan 2012 07:37:24 -0500, PeterD wrote:
Not *my* concept.
Goes back to about 1903. about a dozen or so installed worldwide.
Most decommissioned before and during WWII.
There's one in Sweden that still gets run up, once a year.
*I* never claimed that 1kHz translates to *any* RPM. That was someone else.
What is a generator "head", BTW?
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
Read the link:
Not *my* concept.
Goes back to about 1903. about a dozen or so installed worldwide.
Most decommissioned before and during WWII.
There's one in Sweden that still gets run up, once a year.
*I* never claimed that 1kHz translates to *any* RPM. That was someone else.
What is a generator "head", BTW?
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
P
PeterD
Guest
On 1/28/2012 1:45 PM, Fred Abse wrote:
be!)
A generator head is the part that makes the electricity, and is
(typically) attached to an engine or other motivating device (water
wheel or turbine).
--
I'm never going to grow up.
OK, not your idea, sorry I implied that. (Or said it, as the matter may
be!)
A generator head is the part that makes the electricity, and is
(typically) attached to an engine or other motivating device (water
wheel or turbine).
--
I'm never going to grow up.
F
Fred Abse
Guest
On Mon, 30 Jan 2012 08:29:41 -0500, PeterD wrote:
generator, the whole installation is a "generating set".
Maybe it's power-station-speak.
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
Never heard it called that before. To me, the electrodynamic part is a
generator, the whole installation is a "generating set".
Maybe it's power-station-speak.
--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)