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Regenerative braking in S stock
While doing a bit of idle research into the upcoming Standard Stock
(aka 'S' Stock) being designed for the Underground's Sub Surface Lines, I came across an interesting note which stated that regenerative braking is to be provided and used by the S stock on the SSL lines, and _only_ on the SSL lines - the S stock running District Line services to Richmond and Wimbledon will not regenerate when they are on NR metals. I'm guessing that the trains will achieve this by using some kind of mechanism which can detect the voltage level of the negative pole of the traction circuit and subsequently cut in the regen mechanism when the negative pole is within the appropriate voltage range. Does anyone know how this could be accomplished? |
Regenerative braking in S stock
TheOneKEA wrote: I'm guessing that the trains will achieve this by using some kind of mechanism which can detect the voltage level of the negative pole of the traction circuit and subsequently cut in the regen mechanism when the negative pole is within the appropriate voltage range. Does anyone know how this could be accomplished? Roger Ford, probably. -- gordon |
Regenerative braking in S stock
On Mon, 13 Nov 2006, TheOneKEA wrote:
While doing a bit of idle research into the upcoming Standard Stock (aka 'S' Stock) being designed for the Underground's Sub Surface Lines, I came across an interesting note which stated that regenerative braking is to be provided and used by the S stock on the SSL lines, At last! and _only_ on the SSL lines - the S stock running District Line services to Richmond and Wimbledon will not regenerate when they are on NR metals. ISTR a Doctor Who season finale along much the same lines. Sorry. I'm guessing that the trains will achieve this by using some kind of mechanism which can detect the voltage level of the negative pole of the traction circuit and subsequently cut in the regen mechanism when the negative pole is within the appropriate voltage range. Does anyone know how this could be accomplished? Using the running rails as a voltage reference would be the obvious way to do it. AIUI, there is a voltage across them from track circuits, but it's small enough that it shouldn't matter. However, i wouldn't be at all surprised if the way it actually worked was that the driver had to flip a switch to turn the regenerator off! tom -- Osteoclasts = monsters from the DEEP -- Andrew |
Regenerative braking in S stock
Manual switching is not fast enough - regen was always a problem on LUL due
to conductor rail gaps and no through train power bus being allowed. It has become viable with solid state switching which is fast enough to detect the gap and virtually instantaneously divert the current to braking resistors, etc on the train (temporary loss of braking would be undesirable, at the least!). Taking this a stage further it would be relatively straightforward to detect whether the negative rail is at LUL type potential (i.e truly a negative rail) or at earth potential as on NR tracks. I don't know if this is the way it is going to be done, but is certainly feasible. Peter PS I presume that regen will not be allowed on NR sections due to the potentially enhanced performance of "conventional" NR stock in the section when regen is taking place. -- Peter & Elizabeth Corser Leighton Buzzard, UK "Tom Anderson" wrote in message h.li... On Mon, 13 Nov 2006, TheOneKEA wrote: While doing a bit of idle research into the upcoming Standard Stock (aka 'S' Stock) being designed for the Underground's Sub Surface Lines, I came across an interesting note which stated that regenerative braking is to be provided and used by the S stock on the SSL lines, At last! and _only_ on the SSL lines - the S stock running District Line services to Richmond and Wimbledon will not regenerate when they are on NR metals. ISTR a Doctor Who season finale along much the same lines. Sorry. I'm guessing that the trains will achieve this by using some kind of mechanism which can detect the voltage level of the negative pole of the traction circuit and subsequently cut in the regen mechanism when the negative pole is within the appropriate voltage range. Does anyone know how this could be accomplished? Using the running rails as a voltage reference would be the obvious way to do it. AIUI, there is a voltage across them from track circuits, but it's small enough that it shouldn't matter. However, i wouldn't be at all surprised if the way it actually worked was that the driver had to flip a switch to turn the regenerator off! tom -- Osteoclasts = monsters from the DEEP -- Andrew ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Regenerative braking in S stock
"Peter Corser" wrote in message ... Manual switching is not fast enough - regen was always a problem on LUL due to conductor rail gaps and no through train power bus being allowed. It has become viable with solid state switching which is fast enough to detect the gap and virtually instantaneously divert the current to braking resistors, etc on the train (temporary loss of braking would be undesirable, at the least!). Taking this a stage further it would be relatively straightforward to detect whether the negative rail is at LUL type potential (i.e truly a negative rail) or at earth potential as on NR tracks. I don't know if this is the way it is going to be done, but is certainly feasible. Peter PS I presume that regen will not be allowed on NR sections due to the potentially enhanced performance of "conventional" NR stock in the section when regen is taking place. -- Peter & Elizabeth Corser Leighton Buzzard, UK The track power supplies have to be able to accept regeneration without identifying it as a fault, i.e. transfer the incoming power to elsewhere in the system with a demand. The system nominal voltage shouldn't rise significantly. A lot of NR stock is capable of regeneration, but it is the infrastructure that limits its use. I doubt this applies to the old wrecks that meet LU at Richmond/Gunnersbury though... Paul |
Regenerative braking in S stock
Tom Anderson wrote:
snip Using the running rails as a voltage reference would be the obvious way to do it. AIUI, there is a voltage across them from track circuits, but it's small enough that it shouldn't matter. When the train is there the running rails are at the same potential, the train axles providing the short circuit between them. -- Cheers for now, John from Harrow, Middx remove spamnocars to reply |
Regenerative braking in S stock
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Regenerative braking in S stock
On Tue, 14 Nov 2006, John Shelley wrote:
Tom Anderson wrote: Using the running rails as a voltage reference would be the obvious way to do it. AIUI, there is a voltage across them from track circuits, but it's small enough that it shouldn't matter. When the train is there the running rails are at the same potential, the train axles providing the short circuit between them. Doh! Of course. tom -- Come on thunder; come on thunder. |
Regenerative braking in S stock
On Tue, 14 Nov 2006, Peter Corser wrote:
PS I presume that regen will not be allowed on NR sections due to the potentially enhanced performance of "conventional" NR stock in the section when regen is taking place. That would be highly entertaining. Extremely dangerous, but entertaining! tom -- Come on thunder; come on thunder. |
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