piclist 2002\09\03\033559a >
Thread: The real history of why 60Hz and much more
picon face BY : Morgan Olsson email (remove spam text)

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.


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