"Acrosticus" wrote in message
...
From: Michael Bell
Date: 09/08/2003 22:28 GMT Daylight Time
Current can't be increased because it is
limited by the crosssection of the overhead wire, at least not
without it overheating, sagging and other undesireable behaviour.
Unless you install wire with a greater cross sectional area of course,
which is
more difficult to keep up in the air because it'll be heavier, so I think
you're right there.
But
if you double the voltage at the same current, you double the power.
At least that's my thinking.
And you seem to be right here two. Since volts x amps = watts, double the
voltage whilst keeping the amperage the same and you've doubled the power
too.
Don't forget loaded voltage drop - that is often a major limitation in the
design length of a power feeder, not the absolute current carrying capacity
of cable or rail. When the train is drawing power at the far end of a
section, with higher voltage but with the same old feeder spacing, more
current might be passed by the same conductor without voltage dropping by so
much as a proportion of the feed.
--
Mark