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'[OT]: The real history of why 60Hz and much more'
2002\08\25@161032 by Peter L. Peres

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www.antiquewireless.org/otb/60cycles.htm

Be sure to check the main URL

http://www.antiquewireless.org/

and access the excellent material there on radio history and much more.

Peter

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2002\08\25@164641 by Morgan Olsson

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Peter L. Peres wrote:
>http://www.antiquewireless.org/otb/60cycles.htm

Yes different freq is optimal for different purposes.

IIRC still railways around here use 16 2/3 Hz.

Some industries use 400Hz to drive efficient compact motors (i.e durable handheld heavy duty AC motor power tools) (50Hz motor of same power would have been too heavy)

Amazingly even very large generators of 600MW now run at 3000rpm direct on steam turbine shaft.  (nuclear plant)  Impressive.

Just wondering why USA settled for 60Hz while most of the world settled for 50Hz?
And also different voltage.  We dropped the last 127 and 110 Volts decades ago...

... And the TV systems ... ;)

/Morgan

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'[OT]: The real history of why 60Hz and much more'
2002\09\02@114658 by Martin McCormick
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Morgan Olsson writes:
>Just wondering why USA settled for 60Hz while most of the world settled for 50
>Hz?
>And also different voltage.  We dropped the last 127 and 110 Volts decades ago

       I also find this topic interesting because a lot of
electrical measurement units were strictly standardized very
early on.

       I don't think that even the United States started out
very uniformly in the late 1800's.  There were Edison's DC power
plants and, as previously stated, several frequencies of AC for
various parts of the country depending on where one lived.

       We must have had 50-cycle AC in the Western United States
at one time because I have heard that the Hoover Dam was
originally designed to provide 50-HZ service but was made to
produce 60-hz service by the time it was completed by simply
spinning the turbines faster.

       It would have been nice if everybody in the world had
standardized on one power line frequency and voltage, but people
just didn't think that way when such a thing could have been
done.

       As far as I know, the main two sources for industrial
technology in the late 19TH and early 20TH centuries were the
United States and Europe with Europe having the larger influence
in the world at the time.  What with colonialism and
long-established trade practices, a number of countries in the
rest of the world either bought technology or used expertise or
both from Europe so that's how they got started in using the
electrical power systems they use today.

       Neither 50 nor 60-HZ AC has a clear advantage so we ended
up with what we have.

Martin McCormick WB5AGZ  Stillwater, OK
OSU Center for Computing and Information Services Network Operations Group

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2002\09\02@133618 by Morgan Olsson

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Thank you Martin McCormick, good points.

One addition note:

Until about ten yeras ago some countries in Europe had 220V Nordic, Germany(?)), other had 240V (GB, France...)
Now all(?) have officially 230V, and all new installations are made to deliver 230.
All old units still work, as 230V (plus variation) is within spec of both 220 and 240V old appliance)

Nice middle road.

/Morgan

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2002\09\02@174549 by Jim

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   "Neither 50 nor 60-HZ AC has a clear advantage
    so we ended up with what we have."


Considered in pure abstraction on an e-mail list without
the reality of the physics being involved - probably not.

But when considering the design of power transmission plants
and systems and SUDDENLY realizing that transformers (LARGE
TRANSFORMERS) must now be sized that much larger for a 50-Hz
system on account of the magnetic flux that results during
each peak of a sinusoid on a 50 Hz system as opposed to than
seen on a 60 Hz system - this minor difference translates into
considerable cost and weight savings over time ...

RF Jim


{Original Message removed}

2002\09\02@212247 by Martin McCormick

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       I don't disagree with that at all, but just how much real
difference would a 17% difference in frequency cause in the
physical design of the transformers?  A slight reduction in
frequency would also be more favorable when calculating power
factor.

       We probably should have all chosen a much higher
frequency than we did for the sake of the distribution system but
that would bring lots of other problems in to the picture.  If,
for example, we had chosen 400 HZ, the transformers would sure be
a lot smaller and lighter.  Fluorescent lights would appear to
burn without a trace of flicker in them.  Motors would be much
smaller than their 50 or 60-HZ counterparts.  Power supplies
could get by with much smaller filter capacitors, etc.

       On the down side, inductive reactance would always be
much more of a factor in long transmission runs.  One other thing
to think of.  Anyone who has ever been near a 400-HZ power system
knows that it is very irritating to listen to.

       We used to have a motor-generator set which produced
400-HZ AC for our IBM main frame.  The MG set, of course whined
loudly at 800 HZ, but the room where the actual main frame was sang
right along with it from every transformer.

       It is hard enough to keep 50 and 60 HZ energy out of
sound systems.  I can imagine trying to keep 400-HZ signals out.
We'd all sound like we were in an airplane.

       Just as an anecdote, the building I worked in was briefly
cut over to a standby power generator one day after a pigeon went
from carbon-based life form to just plain old carbon in one of
our sub stations.  The throttle on the generator wasn't set
properly and our power frequency went as low as 55 HZ for several
minutes.

       It was odd hearing the different notes of the air
handlers and other motors in the building as they followed the
generator speed.

       People noticed the fluorescent lights strobing more so at
near 50 HZ, but nothing melted.

       The voltage was still okay and we thought everything was
good enough, but there was one thing we forgot about.

       Our UPS's at the time, were using ferro-resonant
transformers which condition the AC signal by brute-force
filtering on the primary side.  They have a motor-start-type
capacitor and they do fine when they see the proper line
frequency, but this day, they weren't seeing the right frequency
at all.

       The UPS's all went to battery mode and we were too busy
doing other stuff to notice until they shut themselves down after
their batteries ran down.  So much for un-interruptible power.

Martin McCormick

Jim writes:
{Quote hidden}

>{Original Message removed}

2002\09\03@033559 by Morgan Olsson

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Hej Jim. Tack för ditt meddelande 22:43 2002-09-02 enligt nedan:
>considering the design of power transmission plants
>and systems and SUDDENLY realizing that transformers (LARGE
>TRANSFORMERS) must now be sized that much larger for a 50-Hz
>system on account of the magnetic flux that results during
>each peak of a sinusoid on a 50 Hz system as opposed to than
>seen on a 60 Hz system - this minor difference translates into
>considerable cost and weight savings over time ...

That´s strange -i´ve heard the opposite:

Generally higher frequency is better for small devices, low freq for large.  Examples: railroad used (still uses?) 16 2/3Hz, and switched power supplies use 30+ Khz, some tiny converters 1MHz+.  
So losses in *large* motors and transformers is higher at 60Hz than 50.
That also go for losses along transmission lines.
(very long lines use DC for similar reasons, plus DC makes continous use of "peak voltage")

Savings for 60 Hz is in small devices as the magnetics need to be relatively large for the relative to size low frequency.  Radios etc in i.e households, small saving each, but plenty of them.

It is the usual problem of dimensionning, not to make too expensive small units, and not too hig losses in big units.  The grid of course has to have same freq everywhere...

Speaking about saving, 230V saves a lot copper over 110V; as the conductor area need to be FOUR TIMES larger for the same resistive loss at half the voltage.

How many tonnes does make in US? ;)

Also, i have experienced more problems with low voltages in old connectors, as it often get very hot, making fire hazard, but at 230V lower current, and if it is arching it is high enough voltage to arc and either weld together or melt apart. -But that´s mayby just coincidences, and mainly on experience on 230 and 24V respectively.

/Morgan

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2002\09\03@085607 by Walter Banks

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Morgan Olsson wrote:

> Just wondering why USA settled for 60Hz while most of the world settled for 50Hz?
> And also different voltage.  We dropped the last 127 and 110 Volts decades ago...
>
The voltage in the US is 110v/60Hz Canada is 117v/60hz Japan is 100
volts.
Ontario (as someone else noted ) was 25 Hz. Whe in was teenager
I had an old radio designed for 25Hz. There was a significant
amount of iron in its power transformer.

w..

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2002\09\03@093710 by Jim

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  "That4s strange -i4ve heard the opposite:
  Generally higher frequency is better for
  small devices, low freq for large."

I don't understsand what point you're trying to
make overall in your post regarding freq of AC - could
just be me this morning ...

A savings can still be had by using a slightly higher
freq than 50 Hz and I see *no* benefit to using a
frequency as low as 16 2/3 Hz. It *just* requires
that you expend more money in more and larger core
to accomodate higher flux densities for more time
during a 'cycle' ...

Let us all not forget that as a wire in a generator
'cuts' lines of magnetic force that it requires force
to move that wire and (simplifying things greatly now)
the greater the current flow the more force is required.

But - as the dip in the sinusoid occurs - that force goes
to zero. Here is where 3-phase comes in. 3-phase makes
better use of the 'turning force' in a gens than a single
phase does.

DC Transmission of HV power has been tested and to my last
knowledge is in use in a few places in the world. The benefits
are obvious for any one who knows transmission (RF) line
theory and the closely associated knowledge of losses
duw to a variety of causes ...

BTW - to all those args on 240V in the US - we *have* 240V
available for all high-current devices such as water pumps,
blower motors, water heaters and air compresssors - and I
have a LARGE HP 0-40V 0-50Amp Power Supply on 240V - it is
just individual outlets reachable by the occupants of
dwellings that are 120 V ...


RF Jim


   "Our ability to manufacture fraud has exceeded
    our  ability to detect it."

    - Al Pacino as Viktor Taransky in the movie 'Simone'


{Original Message removed}

2002\09\03@095440 by Jim

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     "The voltage in the US is 110v/60Hz"

Update: It's closer to 120 VAC than anything else.

(For awhile TP&L *was* supplying us with 125 VAC and
that was back when my neighbor complained about bulbs
not lasting ...)

RF Jim

{Original Message removed}

2002\09\03@102424 by Morgan Olsson

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Hej Jim. Tack för ditt meddelande 14:37 2002-09-03 enligt nedan:
>I don't understsand what point you're trying to
>make

No point, just seeking what is good and bad for different systems.

And i do´nt think some systems used 25Hz or 16 2/3 Hz just because they where stupid, it probably made at least something easier=cheaper.  For example higher freq on large units make higher losses (induction currents inside wires, and magnetic (re-)magnetisation in (iron)cores).

On the other hand low frequency demand lots of turns and large cores on small devices.

Interestingly 25Hz = 50Hz/2, and (16 2/3)Hz = 50/3, so rotatig synchronous electromachines can easily convert between thoose three.

Agreed, three phase is very neat and make distribution, motors, etc more efficient.  Three phase is AFAIK used in every building in Europe, 3x230. (measured phase-neutral)  All phases used by stoves, washing machine etc, and regular outlets use one phase + neutral.

/Morgan

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2002\09\03@111056 by Jim

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 "And i do4nt think some systems used 25Hz or 16 2/3 Hz
  just because they where stupid, it probably made at least
  something easier=cheaper."

Therein lies the key - they probably had rotary machinery and
designs *already* functional at those frequencies - it's
key to remember that a lot of technology like this is more
"evolvolutionary" than revolutionary (no pun intended) and
who, early on, knew what the implications were for one
choice over another?

The design of large motors and generators has got to be
a non-trivial task (I've never done it and probably never
will!) when designing something that has reliability into
years for MTBF - so I think the early low-freq choices
were more of an acceptance of lower-RPM generators (and
such) than a full comprehnsion of *all* factors involved ...

RF Jim




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