|
|
Post by q8 on Mar 26, 2005 19:07:15 GMT
 I'd like to tap someone's brains. ('cos I ain't got none) about a suggestion I sent to TfL and Metronet. as Follows:-  We had some buses where I live that had some sort of magnetic brake on the drive shaft of the vehicle powered I believe from the batteries. This brake was extremely effective without being fierce. The vehicles I think were built by MCW. My suggestion anchored on the fact that as most modern trains used the dynamic brake to stop with and the current so generated is dumped over the resistances why not make use of it in the following manner. Fit the axles of trailer cars with permanent magnets and use the current from the motors during braking to retard the turning motion of said axles and aid braking. In this way ALL the axles on the train could be used for braking not just the motored ones. The usual tread brake coming at 4mph as now. This would further cut down on brake block use and possibly flats too. Not to mention reduction of heat in the system from all these mobile electric fires dashing about. As I say it's only an idea and I don't know the feasibility of it so perhaps someone with more knowledge of all that could tell us if it would work? 
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 26, 2005 19:49:34 GMT
1. How large a set of electromagnetic coils would be needed to brake a tube-profile train, as opposed to a subsurface-profile train or a full-size NR train?
2. Can existing IGBT-based traction systems provide sufficient energy to power a nontrivial number of magnetic axle brakes?
3. Can they be made failsafe?
4. Will they generate any significant amount of thermal energy?
5. Can they work in concert with regenerative braking?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 26, 2005 20:57:53 GMT
Right - off the subject of trains here... The buses you refer to are MCW Metrobuses, they have an integral retarder within the Gearbox (a Voith D851), this works by sending the oil within the gearbox the wrong way. They tend to be rather fierce when they first cut-in, and very noisy. I've been told of Metrobuses actually locking up their rear wheels on a wet road due to the retarder. All the punters think you can't drive as their heads go like nodding dogs!  The magnetic braking system to which you refer is a Telma, often fitted to coaches as a hand control, applied in steps. I suppose you'd need a pretty big one to stop a train. Both of the above are retarders, and as such are secondary braking and only usefull at speed (i think), the main braking is still done by the actual service brake. Doesn't the rheostatic brake only act as a secondary brake to LUL trains? Sorry to bring buses into this thread a second time  |
|
Colin
Advisor
My preserved fire engine!
Posts: 11,310
|
Post by Colin on Mar 27, 2005 11:31:45 GMT
Perhaps Solidbond's technical knowledge would be useful on this subject.........?!
|
|
I'd like to tap someone's brains. ('cos I ain't got none) about a suggestion I sent to TfL and Metronet. as Follows:-
We had some buses where I live that had some sort of magnetic brake on the drive shaft of the vehicle powered I believe from the batteries. This brake was extremely effective without being fierce. The vehicles I think were built by MCW. My suggestion anchored on the fact that as most modern trains used the dynamic brake to stop with and the current so generated is dumped over the resistances why not make use of it in the following manner. Fit the axles of trailer cars with permanent magnets and use the current from the motors during braking to retard the turning motion of said axles and aid braking. In this way ALL the axles on the train could be used for braking not just the motored ones. The usual tread brake coming at 4mph as now. This would further cut down on brake block use and possibly flats too. Not to mention reduction of heat in the system from all these mobile electric fires dashing about. As I say it's only an idea and I don't know the feasibility of it so perhaps someone with more knowledge of all that could tell us if it would work? 
