Increase AC mains frequency?

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

 

[John Larkin]

On Wed, 19 Mar 2008 09:25:13 -0700 (PDT), mrdarrett@gmail.com wrote:

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

The line frequency is already optimized, 50 or 60 Hz depending on some
tradeoffs.

Synchronous and induction motors would run at 60,000 RPM.

Transformers would scream.

Skin loss would go way up on transmission lines.

Generation would be difficult.

John

 

[Michael Black]

(mrdarrett@gmail.com) writes:

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

The transmission of the signals would probably be lossier, and of course
there'd be more radiation of the signal (to cause interference) since the
wiring would be more efficient at radiating the signal at higher frequencies.

You don't have to cook up such a scenario to get an answer.

Years ago, and presumably still, aircraft (and I think some ships) used
400Hz AC so the transformers would be smaller.

And any switching supply rectifies the AC line directly, turns it into
a comparatively high frequency, so the transformer that actually does
the voltage conversion can be smaller.

It would never happen, unles someone was completely starting from scratch
in some isolated spot. The changeover, ie the replacement of everything,
would be too costly.

Micahel

 

[Don Bowey]

On 3/19/08 9:25 AM, in article
4c0bff45-372c-4720-bbbe-0297b785cc02@e6g2000prf.googlegroups.com,
"mrdarrett@gmail.com" <mrdarrett@gmail.com> wrote:

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

Primarily higher line losses caused by higher current.

 

[Paul E. Schoen]

<mrdarrett@gmail.com> wrote in message
news:4c0bff45-372c-4720-bbbe-0297b785cc02@e6g2000prf.googlegroups.com...

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

A better idea might be to use DC for distribution, as is already done for
high voltage long haul transmission. I think losses are about 1/2 of what
they are for 60 Hz AC. Each household could have, essentially, a motor
drive type inverter for any AC only electronics. But many appliances are
now using small three phase induction motors with their own little V/F
inverters, and the first thing they do is convert the AC line to DC.
Computers and other similar electronics will happily run on 150 VDC. Such a
system would also work well for battery backup.

There are safety issues with DC, but actually 50/60 Hz AC is a dangerous
frequency because it causes fibrillation. DC basically makes your muscles
contract so you can't let go.

Paul

 

[Phil Allison]

"Paul E. Schoen = mind numbingly stupid ASS"

A better idea might be to use DC for distribution, as is already done for
high voltage long haul transmission. I think losses are about 1/2 of what
they are for 60 Hz AC. Each household could have, essentially, a motor
drive type inverter for any AC only electronics.

** Straight back to the 1920's.

Everything the Schoen ASS says is dangerous, stupid and WRONG.

Hee, haw, hee haw, hee haw .......


....... Phil

 

[Michael A. Terrell]

Phil Allison wrote:

Hee, haw, hee haw, hee haw .......

There's a new donkey in town.


--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
* drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic.

http://improve-usenet.org/index.html

 

[David L. Jones]

On Mar 20, 3:44 am, et...@FreeNet.Carleton.CA (Michael Black) wrote:

(mrdarr...@gmail.com) writes:
If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

The transmission of the signals would probably be lossier, and of course
there'd be more radiation of the signal (to cause interference) since the
wiring would be more efficient at radiating the signal at higher frequencies.

You don't have to cook up such a scenario to get an answer.

Years ago, and presumably still, aircraft (and I think some ships) used
400Hz AC so the transformers would be smaller.

And any switching supply rectifies the AC line directly, turns it into
a comparatively high frequency, so the transformer that actually does
the voltage conversion can be smaller.

It would never happen, unles someone was completely starting from scratch
in some isolated spot. The changeover, ie the replacement of everything,
would be too costly.

Micahel

Speaking of isolated systems...

I've worked on marine seismic survey gear that uses 2KHz for power
distribution along the up to 10km line lengths used. The driver being
the smaller transformer sizes required when you have to fit stuff into
70mm diameter cables.

But similar competing systems also use DC for distribution, and I've
worked on the specification and design of a 10km+ system that used
600V DC for distribution. Due to voltage drop you could get less than
100V at the tail end of the system, so the DC-DC converter had to be
designed for a 70V-600V input span.

Dave.

 

[Bob Eld]

"David L. Jones" <altzone@gmail.com> wrote in message
news:d7ecea72-fb06-4560-9eaa-f4aa6f60a486@s19g2000prg.googlegroups.com...

On Mar 20, 3:44 am, et...@FreeNet.Carleton.CA (Michael Black) wrote:
(mrdarr...@gmail.com) writes:
If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

The transmission of the signals would probably be lossier, and of course
there'd be more radiation of the signal (to cause interference) since
the
wiring would be more efficient at radiating the signal at higher
frequencies.

You don't have to cook up such a scenario to get an answer.

Years ago, and presumably still, aircraft (and I think some ships) used
400Hz AC so the transformers would be smaller.

And any switching supply rectifies the AC line directly, turns it into
a comparatively high frequency, so the transformer that actually does
the voltage conversion can be smaller.

It would never happen, unles someone was completely starting from
scratch
in some isolated spot. The changeover, ie the replacement of
everything,
would be too costly.

Micahel

Speaking of isolated systems...

I've worked on marine seismic survey gear that uses 2KHz for power
distribution along the up to 10km line lengths used. The driver being
the smaller transformer sizes required when you have to fit stuff into
70mm diameter cables.

But similar competing systems also use DC for distribution, and I've
worked on the specification and design of a 10km+ system that used
600V DC for distribution. Due to voltage drop you could get less than
100V at the tail end of the system, so the DC-DC converter had to be
designed for a 70V-600V input span.

Dave.

What? What the hell kind of a system would drop 83% of it's voltage in the
line? That makes zero sense. If the DC line losses are so great then the
voltage must be higher to keep the current at a reasonable level.

The best way is a plus and minus DC system then the insulation requirements
are about 2.8 times less than that required for an AC system of similar
voltage. Voltage handling in the switches and electronics is 1/2 of the
actual voltage on the line. Furthermore there are no skin effect
considerations or inductive or capacitive loses in the line. Conversion at
either end can be at high frequencies, 20kHz or higher keeping the magnetics
very small and compact.

 

mrdarrett@gmail.com wrote:

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Some airplane/submarine systems are supposedly 400 Hz AC, which let's you
have smaller transformers at the price of less efficiency (asfaik) and more
electromagnetic interference.
Also skineffect comes into play and increase losses with higher frequency.

However there might be a more optimal frequency between 60 - 400 Hz.
(any suggestion?)

For the last distribution step (less than 1200V) it might be useful with
DC distribution due efficient SMPS. And that many appliancies anyway will
make DC of the mains as a first step.

Still even if you would start from scratch on an isolated island. The cost
to order/special manufacture equipment for an odd mains type can be
prohibitive. The only exception being equipment that rectify anyway.

 

[David L. Jones]

On Mar 21, 4:14 am, "Bob Eld" <nsmontas...@yahoo.com> wrote:

"David L. Jones" <altz...@gmail.com> wrote in messagenews:d7ecea72-fb06-4560-9eaa-f4aa6f60a486@s19g2000prg.googlegroups.com...



On Mar 20, 3:44 am, et...@FreeNet.Carleton.CA (Michael Black) wrote:
(mrdarr...@gmail.com) writes:
If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

The transmission of the signals would probably be lossier, and of course
there'd be more radiation of the signal (to cause interference) since
the
wiring would be more efficient at radiating the signal at higher
frequencies.

You don't have to cook up such a scenario to get an answer.

Years ago, and presumably still, aircraft (and I think some ships) used
400Hz AC so the transformers would be smaller.

And any switching supply rectifies the AC line directly, turns it into
a comparatively high frequency, so the transformer that actually does
the voltage conversion can be smaller.

It would never happen, unles someone was completely starting from
scratch
in some isolated spot. The changeover, ie the replacement of
everything,
would be too costly.

Micahel

Speaking of isolated systems...

I've worked on marine seismic survey gear that uses 2KHz for power
distribution along the up to 10km line lengths used. The driver being
the smaller transformer sizes required when you have to fit stuff into
70mm diameter cables.

But similar competing systems also use DC for distribution, and I've
worked on the specification and design of a 10km+ system that used
600V DC for distribution. Due to voltage drop you could get less than
100V at the tail end of the system, so the DC-DC converter had to be
designed for a 70V-600V input span.

Dave.

What? What the hell kind of a system would drop 83% of it's voltage in the
line? That makes zero sense.

It does if you knew the first thing about marine seismic cable
systems.
In marine seismic systems there is a very delicate balance and trade-
off between the gauge of the copper allowed (i.e. it's weight) and the
distribution of the hundred or so connected point loads along the
system. Everything, including the complex cabling, electronics,
connectors (50 pins + fibre) and buoyant flotation material required
to keep the entire system floating in the ocean must all be contained
within a small diameter in the order of 60mm.
DC-DC converter modules are distributed at regular intervals along the
cable (which can be up to 10km or more), and these modules can be
randomly placed along the cable at any time. So they must be able to
handle the highest voltage at the top end, or the lowest voltage at
the tail end.
And being modular based means you can have several hundred connection
points in series with the system, all with their associated worst case
tolerances.
Total load on the system was many thousands of watts.
So add up small diameter copper, hundreds of connections and point
loads, and you get some very big losses along the system. It's just
the bizarre nature of the business.

If the DC line losses are so great then the
voltage must be higher to keep the current at a reasonable level.

That's why the highest possible DC voltage was used. Several factors
limited the upper voltage allowed.

Conversion at
either end can be at high frequencies,
20kHz or higher keeping the magnetics
very small and compact.

We used 64KHz, sychronised with other electronics in the complex (up
to 10,000 channel) sampling system.

Dave.

 

[NewsGroups]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:64dqvoF2a7clgU1@mid.individual.net...

"Paul E. Schoen = mind numbingly stupid ASS"


A better idea might be to use DC for distribution, as is already done for
high voltage long haul transmission. I think losses are about 1/2 of what
they are for 60 Hz AC. Each household could have, essentially, a motor
drive type inverter for any AC only electronics.


** Straight back to the 1920's.

Everything the Schoen ASS says is dangerous, stupid and WRONG.

Hee, haw, hee haw, hee haw .......

You must be an anus living in a very remote area not to know about
the high voltage DC transmission lines in use. The losses are much lower
than conventional AC.
But then , a person such as you, with very limited education, would not be
able to understand the term efficiency.

...... Phil

 

[Mike Silva]

In a related question, is there any consensus as to whether 120V or
240V mains are better, overall (I can see (some of) the advantages and
disadvantages of each, just not the total evaluation)?

 

[Don Bowey]

On 3/21/08 6:42 AM, in article UpCdnUCJm5TvJn7anZ2dnUVZ_siknZ2d@wightman.ca,
"NewsGroups" <spar@plaus> wrote:

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:64dqvoF2a7clgU1@mid.individual.net...

"Paul E. Schoen = mind numbingly stupid ASS"


A better idea might be to use DC for distribution, as is already done for
high voltage long haul transmission. I think losses are about 1/2 of what
they are for 60 Hz AC. Each household could have, essentially, a motor
drive type inverter for any AC only electronics.


** Straight back to the 1920's.

Everything the Schoen ASS says is dangerous, stupid and WRONG.

Hee, haw, hee haw, hee haw .......


You must be an anus living in a very remote area not to know about
the high voltage DC transmission lines in use. The losses are much lower
than conventional AC.
But then , a person such as you, with very limited education, would not be
able to understand the term efficiency.

You must be a jerk who does not understand the difference between
"Transmission" and "Distribution" lines and configurations.

It appears Phil's education is far less limited than yours, though you
probably understand an anus far better than us.

...... Phil

 

[z]

On Mar 19, 12:25 pm, mrdarr...@gmail.com wrote:

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

sure would. old aircraft (ww II vintage) used to use 400 hz
specifically because the equipment was smaller and lighter.

besides AC clocks, huge industrial motors are slaved to the frequency
by the 3 phase system; no way to practically change that now.

 

[Sjouke Burry]

z wrote:

On Mar 19, 12:25 pm, mrdarr...@gmail.com wrote:
If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael

sure would. old aircraft (ww II vintage) used to use 400 hz
specifically because the equipment was smaller and lighter.

besides AC clocks, huge industrial motors are slaved to the frequency
by the 3 phase system; no way to practically change that now.
The higher frequency would make people go crazy.

I have worked in an Airforce bunker where you were tortured
the whole day with the third harmonics(1200 hz) of the
400 hz mains used there.
Frequencies between 200 and 5000 hz are very irritating and
leak out of any machine using them.
The only cure for these powerfeed frequencies is a wirecutter.

 

[Jamie]

Sjouke Burry wrote:

z wrote:

On Mar 19, 12:25 pm, mrdarr...@gmail.com wrote:

If the power companies increased the frequency of AC mains current
from 60 Hz to something more like 1 kHz, would this make transformer
sizes smaller for AC equipment?

Besides older-style AC clocks no longer keeping correct time, what
would the downside to increased AC frequency be?

Michael


sure would. old aircraft (ww II vintage) used to use 400 hz
specifically because the equipment was smaller and lighter.

besides AC clocks, huge industrial motors are slaved to the frequency
by the 3 phase system; no way to practically change that now.

The higher frequency would make people go crazy.
I have worked in an Airforce bunker where you were tortured
the whole day with the third harmonics(1200 hz) of the
400 hz mains used there.
Frequencies between 200 and 5000 hz are very irritating and
leak out of any machine using them.
The only cure for these powerfeed frequencies is a wirecutter.
I find that the OFF Switch is easier to find than wire cutters

lying around.


--
"I'd rather have a bottle in front of me than a frontal lobotomy"

"Daily Thought:

SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.
http://webpages.charter.net/jamie_5"

 

[NewsGroups]

"Don Bowey" <dbowey@comcast.net> wrote in message
news:C4092DA9.B3079%dbowey@comcast.net...

On 3/21/08 6:42 AM, in article
UpCdnUCJm5TvJn7anZ2dnUVZ_siknZ2d@wightman.ca,
"NewsGroups" <spar@plaus> wrote:


"Phil Allison" <philallison@tpg.com.au> wrote in message
news:64dqvoF2a7clgU1@mid.individual.net...

"Paul E. Schoen = mind numbingly stupid ASS"


A better idea might be to use DC for distribution, as is already done
for
high voltage long haul transmission. I think losses are about 1/2 of
what
they are for 60 Hz AC. Each household could have, essentially, a motor
drive type inverter for any AC only electronics.


** Straight back to the 1920's.

Everything the Schoen ASS says is dangerous, stupid and WRONG.

Hee, haw, hee haw, hee haw .......


You must be an anus living in a very remote area not to know about
the high voltage DC transmission lines in use. The losses are much lower
than conventional AC.
But then , a person such as you, with very limited education, would not
be
able to understand the term efficiency.


You must be a jerk who does not understand the difference between
"Transmission" and "Distribution" lines and configurations.

Donnie: the original post to which we are referring did NOT mention
transmission or distribution> It simply asked why not increase the mains
frequency. How much more main can you get than transmission lines.

It appears Phil's education is far less limited than yours, though you
probably understand an anus far better than us.







...... Phil

 

Mike Silva <snarflemike@yahoo.com> wrote:

In a related question, is there any consensus as to whether 120V or
240V mains are better, overall (I can see (some of) the advantages and
disadvantages of each, just not the total evaluation)?

More volt => Less current for the same power => Less copper, Lighter cables,
Less magnetic fields, etc..