Sure you have your facts right Bill?
I understand the iron losses increasing, but why does copper cable 'only use
the outer quarter inch'?
My understanding is that this phenomena kicks in at much higher
frequencies - like above 50KHz.
Another factor in choosing the frequencies may have been to do with
audibility. I can imagine a (say) 800Hz transformer or motor making an
intolerable racket compared to a 50Hz model.
Regards
Ron
..
"Repeating Rifle" wrote in message
...
in article , Lawrence DčOliveiro
at
_zealand wrote on 12/10/04 12:24 PM:
I heard that Tesla wanted mains frequencies to be around 300-400Hz for
this reason. I think the engineers who built the early power plants
(Edison?) felt this was impractical because they couldn't build big AC
generators that could spin that fast.
Wonder how things would be different if the situation could be revisited
today...
Very briefly, the commercial power frequency selected is a tradeoff
between
costs of equipment and size of equipent. Core losses, from the iron in
transformers, increase with frequency. For 60 Hz ac, only about the outer
quarter inch of copper in cables is used. As frequency is increased, less
of
the copper conductor is used. In the end 60 Hz is used for most European
power while 60 Hz was selected for the USA. In aircraft, weight can be
much
more of an economic factor then efficiency. Thus 400 Hz is popular in
aircraft. But realize that only about 0.1 inch thickness of copper is
useful.
Bill