At 07:29 PM 4/16/1999 +1, you wrote:
>> >> >3) 240VAC 3 pin sockets are a national standard.
>> >> I think only the English (and Swiss?) are the ones that want to be
>> >> different to the rest of Europe - in this case anyway (there are many
>> >> others).
>
>> >What about the mains voltage? Does that vary a lot? We're all 240v 50hz.
>> >(In theory, anyway)
>
>> 240V was chosen to be the standard to reduce line losses??? Why 50cyc?
>
>Short answer:
>Why not.
>Or: Why 60 ?
Short answer: Smaller transformers and less copper used.
>Long Answer:
>A willingfull decision of a single person (or group) in the past.
>Lets see: If you want AC (usefull to allow up/downstepping of Voltage)
>some 12-15 Hz are minimum. Also, if you want to have a continious
>electric lighting, the frequency should be above ~40Hz. On the other
>hand, as higher the frequency gets, as harder it is to build usable
>distribution systems - also (more important) for higher frequencies
>you need faster spinning generators (machines at some 500 rpm have
>been hightech around the turn of the century) with higher cost to build
>and maintain or more dense packing to get more coils be powered within
>one turn - and as we know, dense packing is a development problem - when
>a technology is new, the structures are big. Taking this into account,
>usable frequencies for public power systems have been in the 40-100 Hz
>range - now the only task was to pick one. The 60 Hz decison might have
>been based on the idea to continue the line: one minute is 1/60th of
>a hour, and a second is 1/60th of a minute, and a cycle is 1/60th of
>a second ... while the 50Hz idea was based on geting a simple number,
>(serving the needed purpose) with a usable division within the decimal
>system.
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Received on Fri Apr 16 1999 - 12:46:26 BST