Groups > alt.folklore.computers > #150309

Re: optimum power supply for subway/light rail lines

From	"hqhy" <hqhy@nospam.com>
Newsgroups	alt.folklore.computers
Subject	Re: optimum power supply for subway/light rail lines
Date	2015-08-25 04:47 +1000
Message-ID	<d4175aFn4ksU1@mid.individual.net> (permalink)
References	<5932e6a1-4930-466c-8bb8-4baadf9e9e77@googlegroups.com>

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<hancock4@bbs.cpcn.com> wrote in message 
news:5932e6a1-4930-466c-8bb8-4baadf9e9e77@googlegroups.com...
> When streetcars and subways were developed 100 years ago, the used 600V DC 
> for power.  DC motors at the time were easily controlled and 600V was a 
> good voltage for the application.
>
> But that was then.
>
> Now, most systems use AC motors, where control is applied by varying the 
> frequency through sophisticated electronic controls.  The power supply, 
> however, remains close to 600VDC, though somewhat higher voltages are 
> common, such as 650 to 750V.
>
> Given today's needs, what should power supply voltage should be?  Subway 
> and light rail voltages can't be too high as it would be an arcing problem 
> and safety problem.  But should they be AC?

Quite a few of them are.
https://en.wikipedia.org/wiki/Railway_electrification_system

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Thread

optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-24 11:00 -0700
  Re: optimum power supply for subway/light rail lines "hqhy" <hqhy@nospam.com> - 2015-08-25 04:47 +1000
    Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-24 15:01 -0500
  Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-24 14:45 -0500
    Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-24 13:22 -0700
      Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 13:26 -0500
        Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-25 11:48 -0700
          Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 16:12 -0500
            Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-25 20:20 -0700
        Re: optimum power supply for subway/light rail lines danny burstein <dannyb@panix.com> - 2015-08-25 20:28 +0000
  Re: optimum power supply for subway/light rail lines Morten Reistad <first@last.name.invalid> - 2015-08-24 21:42 +0200
    Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-24 15:14 -0500
      Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-25 08:07 -0700
        Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 12:52 -0500
          Re: optimum power supply for subway/light rail lines scott@slp53.sl.home (Scott Lurndal) - 2015-08-25 20:06 +0000
  Re: optimum power supply for subway/light rail lines Jon Elson <elson@pico-systems.com> - 2015-08-24 23:33 -0500
    Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 01:39 -0500
      Re: optimum power supply for subway/light rail lines Morten Reistad <first@last.name.invalid> - 2015-08-25 10:23 +0200
        Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 12:30 -0500
          Re: optimum power supply for subway/light rail lines Morten Reistad <first@last.name.invalid> - 2015-08-25 22:48 +0200
            Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-26 10:44 -0500
              Re: optimum power supply for subway/light rail lines Morten Reistad <first@last.name.invalid> - 2015-08-26 18:03 +0200
              Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-26 12:04 -0700
      Re: optimum power supply for subway/light rail lines Jon Elson <jmelson@wustl.edu> - 2015-08-25 14:15 -0500
        Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 15:15 -0500
          Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-25 13:33 -0700
            Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 15:49 -0500
              Re: optimum power supply for subway/light rail lines danny burstein <dannyb@panix.com> - 2015-08-25 21:00 +0000
                Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 16:37 -0500
                Re: optimum power supply for subway/light rail lines lawrence@cluon.com - 2015-08-25 23:52 +0200
                fluorescents, was: optimum power supply for subway/light rail lines danny burstein <dannyb@panix.com> - 2015-08-25 22:25 +0000
                Re: fluorescents, was: optimum power supply for subway/light rail lines lawrence@cluon.com - 2015-08-26 04:13 +0200
                Re: fluorescents, was: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-25 20:24 -0700
                Re: optimum power supply for subway/light rail lines JimP <solosam90@gmail.com> - 2015-08-25 19:11 -0500
                Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-25 20:36 -0700
                Re: optimum power supply for subway/light rail lines Michael Black <et472@ncf.ca> - 2015-08-26 02:29 -0400
                Re: optimum power supply for subway/light rail lines JimP <solosam90@gmail.com> - 2015-08-26 09:35 -0500
            Re: optimum power supply for subway/light rail lines danny burstein <dannyb@panix.com> - 2015-08-25 20:52 +0000
              Re: optimum power supply for subway/light rail lines "Joseph D. Korman" <joekor@earthlink.net> - 2015-08-28 14:34 -0400
            Re: optimum power supply for subway/light rail lines Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-08-26 04:03 +0000
          Re: optimum power supply for subway/light rail lines danny burstein <dannyb@panix.com> - 2015-08-25 20:36 +0000
    Re: optimum power supply for subway/light rail lines hancock4@bbs.cpcn.com - 2015-08-25 08:10 -0700
      Re: optimum power supply for subway/light rail lines Stephen Sprunk <stephen@sprunk.org> - 2015-08-25 12:18 -0500
        Re: optimum power supply for subway/light rail lines danny burstein <dannyb@panix.com> - 2015-08-25 17:30 +0000

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