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PeterD
Guest
Sat Jan 28, 2012 1:37 pm
On 1/27/2012 12:42 PM, Fred Abse wrote:
Quote:
On Sat, 21 Jan 2012 10:53:11 -0500, krw_at_att.bizzzzzzzzzzzz wrote:
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.
https://secure.wikimedia.org/wikipedia/en/wiki/Alexanderson_alternator
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.
Michael A. Terrell
Guest
Sat Jan 28, 2012 6:35 pm
PeterD wrote:
Quote:
On 1/27/2012 12:42 PM, Fred Abse wrote:
On Sat, 21 Jan 2012 10:53:11 -0500, krw_at_att.bizzzzzzzzzzzz wrote:
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.
https://secure.wikimedia.org/wikipedia/en/wiki/Alexanderson_alternator
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!
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.
Fred Abse
Guest
Sat Jan 28, 2012 7:45 pm
On Sat, 28 Jan 2012 07:37:24 -0500, PeterD wrote:
Quote:
On 1/27/2012 12:42 PM, Fred Abse wrote:
On Sat, 21 Jan 2012 10:53:11 -0500, krw_at_att.bizzzzzzzzzzzz wrote:
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.
https://secure.wikimedia.org/wikipedia/en/wiki/Alexanderson_alternator
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!
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)
PeterD
Guest
Mon Jan 30, 2012 2:29 pm
On 1/28/2012 1:45 PM, Fred Abse wrote:
Quote:
On Sat, 28 Jan 2012 07:37:24 -0500, PeterD wrote:
On 1/27/2012 12:42 PM, Fred Abse wrote:
On Sat, 21 Jan 2012 10:53:11 -0500, krw_at_att.bizzzzzzzzzzzz wrote:
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.
https://secure.wikimedia.org/wikipedia/en/wiki/Alexanderson_alternator
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!
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?
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.
Fred Abse
Guest
Tue Jan 31, 2012 9:19 pm
On Mon, 30 Jan 2012 08:29:41 -0500, PeterD wrote:
Quote:
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).
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)
Cydrome Leader
Guest
Mon Feb 27, 2012 2:58 am
Sjouke Burry <s_at_b> wrote:
Quote:
"Jim Hawkins" <jimhawkins_at_manx.net> wrote in
news:uZ6dnX1KQIiQTIfSnZ2dnUVZ8nCdnZ2d_at_supernews.com:
Jim Hawkins wrote:
Is a mains transformer designed for 60Hz significantly lighter than
one of the same VA rating designed for 50Hz ?
Jim Hawkins
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 ?
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.
Apparently they had line frequencies as 16.66 Hz and other strange stuff
like 25Hz, which was last used in the US for railway lines.
Here's a little about this:
http://www.nycsubway.org/articles/rotary_converter.html
josephkk
Guest
Sun May 20, 2012 8:23 pm
On 26 Jan 2012 23:50:39 GMT, Sjouke Burry <s_at_b> wrote:
Quote:
"Jim Hawkins" <jimhawkins_at_manx.net> wrote in
news:uZ6dnX1KQIiQTIfSnZ2dnUVZ8nCdnZ2d_at_supernews.com:
Jim Hawkins wrote:
Is a mains transformer designed for 60Hz significantly lighter than
one of the same VA rating designed for 50Hz ?
Jim Hawkins
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 ?
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.
I had dips at 2400 and 4800 Hz as well as 1200 when i was done with the
navy.
?-)
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