Can the traction motors in Diesel locomotives be used as Generator(as in Regenerative Braking)?
Traction motors in Diesel locomotives are electric motors, if the process were to be reversed cant it be used as Generator. Why go through all the trouble of resistor banks.
Yes indeed.
Unfortunately, for now all the juice the motors generate in dynamic braking is lost, and there is a LOT of it, too. Depending on the model, a single traction motor can generate up to 700 to 900 amps across a 215 volt field.
The electricity generated needs to go somewhere, so it is dissipated as heat through large grids operating on the same principal as the toaster in every ones kitchen, so there is no need for resistors. The cooling fans for the grids operate on the same current utilizing some of the electricity as well. That is why the pitch of the distinctive "whine" heard when in dynamic braking changes as the engineer changes the position of the dynamic brake controller, as the fans react to the changes in the current, spinning faster or slower.
In addition, dynamic has seen many changes from the first generation models, which were of the "field loop" type. These are long gone, but there remains "flat" (the most common, which responds directly to the position of the controller) and "taper" (rare, usually found only on older diesel electrics and using speed as a part of the operating paradigm) with the sub-categories of "standard," wherein retarding effort drops dramatically at speeds below 12 mph, and "extended range," which develops high retarding effort down to about 3 to 5 mph. Quite useful as the train comes to a stop when in dynamic, helping to keep the slack from running out on the head end.
Sliding wheels when coming to a stop is an issue with extended range dynamic, so most locos have incorporated into the engine (independent) air brake a Dynamic Brake Interlock (DBI) that nullifies the extended range when brake cylinder pressure reaches 12 to 15 psi.
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I’m not entirely sure but I believe Locomotives do use regenerative braking.
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Yes they can be used as generators since that’s exactly what they become when used in dynamic braking.Next year GE is unveiling a freight service engine that is a hybrid.The excess dynamic brake energy is used to recharge banks of batteries that help power the locomotive under power.I had the first one in a train last year.It was the prototype going to California to be displayed in a green fair.It was a GE Evolution number 2010.If you google the GE 2010 i think you can read more about it.
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UPRR engineer
Now its my turn to back Andy up hes right.
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Im a Norfolk Southern Conductor.
Yes indeed.
Unfortunately, for now all the juice the motors generate in dynamic braking is lost, and there is a LOT of it, too. Depending on the model, a single traction motor can generate up to 700 to 900 amps across a 215 volt field.
The electricity generated needs to go somewhere, so it is dissipated as heat through large grids operating on the same principal as the toaster in every ones kitchen, so there is no need for resistors. The cooling fans for the grids operate on the same current utilizing some of the electricity as well. That is why the pitch of the distinctive "whine" heard when in dynamic braking changes as the engineer changes the position of the dynamic brake controller, as the fans react to the changes in the current, spinning faster or slower.
In addition, dynamic has seen many changes from the first generation models, which were of the "field loop" type. These are long gone, but there remains "flat" (the most common, which responds directly to the position of the controller) and "taper" (rare, usually found only on older diesel electrics and using speed as a part of the operating paradigm) with the sub-categories of "standard," wherein retarding effort drops dramatically at speeds below 12 mph, and "extended range," which develops high retarding effort down to about 3 to 5 mph. Quite useful as the train comes to a stop when in dynamic, helping to keep the slack from running out on the head end.
Sliding wheels when coming to a stop is an issue with extended range dynamic, so most locos have incorporated into the engine (independent) air brake a Dynamic Brake Interlock (DBI) that nullifies the extended range when brake cylinder pressure reaches 12 to 15 psi.
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The use of electric traction motors as dynamic brakes isn’t quite the same thing as using them as generators. It is hair-splitting a little, as the motors are effectively being run as generators in order to convert the kinetic energy of the train into electric energy, but the power being generated is not being used. Instead it is being wasted as heat through banks of resistors. It’s only with electric traction where the power generated by the dynamic brake can be returned to the grid that this power can be reused.
The problem with using the traction motors in reverse to generate power is what are you going to use the power for? You only get the supply whenever the dynamic brake is being used, which makes it unreliable and not suitable for any on-train systems. About the only thing you can do with it is to store it in banks of batteries for traction use later.
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yes they can, the axles are powerd by ele.
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SVHR
yup, ya kind of got me confused with the part of resistor banks though. Without regenerated electricity there would be no need for resistor banks or heat grids.
Too bad there isnt a way to recycle all that electricity . . . . . . if only someone would come up with some sort of system of overhead lines to pick up that free electricity and send it back to the grid.
Sometime far off in the future perhaps.
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RR engineer, formerly with the longest electrified railroad in the U.S.
Yes, it is possible, and the same applies to electric trains, which draw power from an external source, that includes trams (US/Canada = streetcars), metro trains, etc.
In London during the tramway era (c.1900 - 1952) there was a steep hill, where one tram would come to a stand at the bottom and wait for another to arrive at the top. Then the tram at the top would descend, with the motor polarity reversed and feeding the resultant current generated back into the system, which the tram at the bottom would use as extra power to climb the hill.
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http://www.londontramways.net/articles/dog_kennel_hill.php
As most have said yes they can, and yes they do provide electricity. but really, one must consider how often a train is in dynamic braking mode. more prominant in hilly and mountainous terrains. flat wide open railroads, if you notice, sometimes purchased their locomotives without dynamic brakes because it was unneeded… no down hills. and there again what are you gonna power with this rarely provided electricity? the prime mover already provides power for all the electrics in both normal and dynamic braking. batteries? well, we are so very far from battery operated mainline freight locomotives. diesel electric is still by far the most efficient. yard locos can be battery operated but never have the need for dynamic braking. so its moot there. as you can see, GM and GE factories have already known for years dissipate the juice into a large metal grid (resistance to heat) and cool it with a fan.
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40 years railfan, student of railroads.
Electric locomotives can feed their braking power back into the overhead wires (as long as there is another train in the system to consume the energy).
In a diesel-electric locomotive you don’t have anywhere to put the extra energy (except a bit for train heating/air-conditioning on passenger trains), so you usually heat up resistor banks with the electric power from the motors, even though that means that you cannot re-use the energy.
You could charge a battery and use that power again to accelerate the train later, then you had a hybrid locomotive, I believe they are testing that in some shunters but there is no large scale application yet.
Another possible solution for short term energy storage would be flywheels.
In a diesel-hydraulic engine you may have a retarder (in addition to friction brakes) that will heat up oil when braking.
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