Tom Anderson wrote:


IMHO It is very likely that I Kingdom Brunel would welcome
electrification. He seemed very keen to find a better, cleaner form
of motive power.

He would have insisted on using 3 phase 37.278kV* electrification at
16.25Hz fed through side contact 3rd and 4th rail - and bugger the
through running!

* there is a logic behind this number. See if you can work it out!

Dunno, but getting three-phase power through two conductors is an
interesting idea.

tom


.... running rail(s) for the third phase. I'm not making this up, it has
been done before, in Italy and elsewhe

http://en.wikipedia.org/wiki/Railway...urrent_systems

On Sat, 9 May 2009, GazK wrote:

Tom Anderson wrote:

IMHO It is very likely that I Kingdom Brunel would welcome
electrification. He seemed very keen to find a better, cleaner form
of motive power.

He would have insisted on using 3 phase 37.278kV* electrification at
16.25Hz fed through side contact 3rd and 4th rail - and bugger the through
running!

* there is a logic behind this number. See if you can work it out!

Dunno, but getting three-phase power through two conductors is an
interesting idea.

... running rail(s) for the third phase. I'm not making this up, it has been
done before, in Italy and elsewhe

http://en.wikipedia.org/wiki/Railway...urrent_systems

That seems a little bit ... yikes.

Thinking about it, though, it's no worse than using the running rails for
current return in a one-phase system, is it? I'm not sure why i thought it
would be.

tom

--
We want to make this easy but if you don't understand how this
works, you have no business controlling the fate of the internet. --
web2.0validator.com

On Sat, 9 May 2009 21:16:22 +0100, Tom Anderson
wrote:

On Sat, 9 May 2009, GazK wrote:

Tom Anderson wrote:

IMHO It is very likely that I Kingdom Brunel would welcome
electrification. He seemed very keen to find a better, cleaner form
of motive power.

He would have insisted on using 3 phase 37.278kV* electrification at
16.25Hz fed through side contact 3rd and 4th rail - and bugger the through
running!

* there is a logic behind this number. See if you can work it out!

Dunno, but getting three-phase power through two conductors is an
interesting idea.

... running rail(s) for the third phase. I'm not making this up, it has been
done before, in Italy and elsewhe

http://en.wikipedia.org/wiki/Railway...urrent_systems

That seems a little bit ... yikes.

Thinking about it, though, it's no worse than using the running rails for
current return in a one-phase system, is it? I'm not sure why i thought it
would be.

I don't know about the Italian system but the American one had single
speed locomotives because the AC motors were synchronous.

Which didn't really matter for the slow speed freight trains in the
Cascades.

tom

"Christopher A. Lee" wrote in message
...
On Sat, 9 May 2009 21:16:22 +0100, Tom Anderson
wrote:

On Sat, 9 May 2009, GazK wrote:

Tom Anderson wrote:

IMHO It is very likely that I Kingdom Brunel would welcome
electrification. He seemed very keen to find a better, cleaner form
of motive power.

He would have insisted on using 3 phase 37.278kV* electrification at
16.25Hz fed through side contact 3rd and 4th rail - and bugger the
through
running!

* there is a logic behind this number. See if you can work it out!

Dunno, but getting three-phase power through two conductors is an
interesting idea.

... running rail(s) for the third phase. I'm not making this up, it has
been
done before, in Italy and elsewhe

http://en.wikipedia.org/wiki/Railway...urrent_systems

That seems a little bit ... yikes.

Thinking about it, though, it's no worse than using the running rails for
current return in a one-phase system, is it? I'm not sure why i thought it
would be.

I don't know about the Italian system but the American one had single
speed locomotives because the AC motors were synchronous.

Which didn't really matter for the slow speed freight trains in the
Cascades.

tom

1) Interesting outcome when one loco in a set failed, the other just sat
there and ground away at the rail, stationary. This was 1920s, no
headlights, the crew had no idea. Can't recall the source - a book I read
somewhere.

2) Back to the 37.278. Well 37.278/ sq rt 2 = 26.34kV ... my AC maths is
too primitive, but sq rt of 2 is a component of the reason.


David down under

On 9 Mai, 22:29, Christopher A. Lee wrote:

I don't know about the Italian system but the American one had single
speed locomotives because the AC motors were synchronous.


The Italians used squirrel cage motors which don't strictly require
synchronous running.

Different speed settings could be obtained by the switching of poles.

Resistors were used for the internediate speeds.

So not too different to a DC setup really.

On 9 Mai, 20:36, GazK wrote:

... running rail(s) for the third phase. I'm not making this up, it has
been done before, in Italy and elsewhe

is still done on many mountain railways in Switzerland and elsewhere.