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Old February 7th, 2008, 01:57 PM   #1
Tri-ring
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MISC | Rail Debate

Ok here is the thread to discuss and debate any and all cocerning rail technology.

First up, potential speed ceiling of electric motors based on size.
On another thread elfabyanos and myself started it with my posting as below.

Quote:
Originally Posted by Tri-ring View Post
No way will it come close to 580Km/h since distributed power system has an inherit limit, smaller motors have lower maximum power output ceilings.
The advantage with distributed power system is less torque is lost through wheel/rail connection creating faster acceleration.
The locomotive style TGV took 20km to reach top speed while the latest Shinkansen N700 series takes less than 13 Km.
This opinion met the following opposition.

Quote:
Originally Posted by elfabyanos View Post
I don't buy that. Locomotives are only a certain size too - if size is an inherent limit for one concept it's a limit for another.
Which was counter by the following;

Quote:
Originally Posted by Tri-ring View Post
It's a simple physics fact.
The answer lies within the amount of wire wrapped within a motor.
If you use the same material, 200M wrapped around a magnetic core will always have stronger output then a motor that only has 100M.
Therefore bigger the mass, potentially you have more space to wrap wire equating to larger output.
The trick is how to balance weight with mass.
Which was finally counterd by the following;

Quote:
Originally Posted by elfabyanos View Post
That's technically correct misguided nonsense. Yes, a bigger motor is more powerful. It also consumes more power. It also takes up more space. And no, it isn't more efficient. The most efficient motors made are absolutely tiny. You've understood one part of the electric motor process, and made incorrect assumptions based on this knowledge.

The JR 500 series has more horsepower than Eurostar, and is a shorter train. Eurostar even uses up about another half car in total on the two cars next to the locos, because there isn't enough space to fit in all the equipment for such a powerful locomotive in the space provided. But there's space under the carriage for the JR 500 to get the same amount of power and more in 16 cars.
This is the full outline.

Next let's look at specs for the two trains.

British Rail Class 373 (Eurostar)
Formation 20 cars (Three Capitals)
Car body Steel
Weight 752 t (Three Capitals, empty)
Power output 12.2 MW 25 kV
Voltage 25 kV, 50 Hz AC
Maximum speed 334.7 km/h (Record)
300 km/h (Service)

Shinkansen 500 series
Formation 16 cars
Body Aluminum alloy honeycomb sandwich body
train set total weight 688t
Power output 18.24 MW
285kW×64 = 18,240kW
Voltage 25 kV AC, 60 Hz overhead
Maximum speed 320 km/h/s (Design)
300 km/h (service)

The 500 series has 64 (285kW) motors in total, on the other hand I was not able to find the number of motors for class 373.
At the end we are comparing apples with oranges so I really can not say much since it is very unlikely the Japanese and French are sharing the same metallurgy technology and/or motor design.
I did mention that the trick is to balance mass with weight.
Weight nor consumption of energy does not necessarily need to become heavier and/or larger proportionally with size, using better design such as coreless motor design and usage of lighter material with stronger magnetic conduction will offset the balance between size with strength and weight.

The trick with distributed power system is how to synchronize the output of all motors at the same level to gain the desired effect but even with stronger overall output with lighter body weight, the single motor for the 500 series maxes out at 285kW which becomes the ceiling for top speed.
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Old February 7th, 2008, 03:20 PM   #2
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Your point was about space. You were saying that because bigger coils produce more power, you need a space big enough to put them i.e. a dedicated loco. You were saying that this was why there is a power ceiling if you restrict the space.

1) It doesn't necessarily follow that you need a dedicated loco because bigger coils produce more power. For this to be necessary there would have to be a requirement that all the required power is produced in one place. This extra requirement may be a practical consideration (though has proven not to be) but certainly doesn't necessitate the original point you made.

2) Your point alos rested on the concept that traction motors are big, and take up a lot of space.

3) One of my local Electrostars if put in a 5 unit formation would be about as long as a Eurostar and put out 7.5 MW. That's without even trying to be a high speed train of any description it would still kick out over two thrids of the power needed to be in Eurostar territory. If you've ever seen an Electrostar they're not exactly pressed for space underneath either.

4) The French AGV will have less potential traction motors because it has about half as many axles as a Shinkansen of equivalent length. So if space was a restriction on Shinkansens, all of a sudden the French have doubled the power output of their traction motors and still managed to find space under the car.

5) As I said, space has been a restriction for Eurostar - they weren't able to fit the power required into the normal space in a locomotive. So space is a problem for both concepts, as I originally stated. All I am trying to point out is that it isn't a problem for just one of the concepts, and certainly not for the reasons you suggest.

6) Traction motors aren't that big. Transformers and other electrics are. This is a motor for a 400 ton minig truck:


See the traction motors here fitting snugly in the bogie - this isn't a tram, it's the bogie of a Union Pacific diesel freight locomotive!


There is space to power a ten car train to 500mph - we just need to develop the technology.

BTW A Eurostar set has 12 traction motors, same amount as a class 390 pendolino. http://therailwaycentre.com/New%20EM...a/EMU_373.html
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Old February 7th, 2008, 04:36 PM   #3
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Quote:
Originally Posted by elfabyanos View Post
Your point was about space. You were saying that because bigger coils produce more power, you need a space big enough to put them i.e. a dedicated loco.
No, my point was that smaller motor will always have lower power ceilings which I have pointed out in my first post.

Quote:
Originally Posted by elfabyanos View Post
1) It doesn't necessarily follow that you need a dedicated loco because bigger
coils produce more power. For this to be necessary there would have to be a requirement that all the required power is produced in one place. This extra requirement may be a practical consideration (though has proven not to be) but certainly doesn't necessitate the original point you made.
I agree but the more motors you place weight gains exponentially, while power output will not.
Simply put if you have a single motor with 100 M of wire and compare it with two small motors that has 75 M of wire each, the strength may be stronger by 50% but the weight/power ratio will be offset due to the total weight of two motors. This means double the motors does not always add up to double efficiency as you postulate because you need to apply additional weight to compensate for additional mechanism needed for mounting, gearing and so on meaning power/weight ratio will only be marginal.

Quote:
Originally Posted by elfabyanos View Post
2) Your point alos rested on the concept that traction motors are big, and take up a lot of space.
Never said that knowing that Shinkansen motors lies beneath the boogies but if you compare a locomotive type and a distributed power system that is both able to obtain 300Km/h commercial speed then the locomotive system will always be faster at minimum setting.


Quote:
Originally Posted by elfabyanos View Post
3) One of my local Electrostars if put in a 5 unit formation would be about as long as a Eurostar and put out 7.5 MW. That's without even trying to be a high speed train of any description it would still kick out over two thrids of the power needed to be in Eurostar territory. If you've ever seen an Electrostar they're not exactly pressed for space underneath either.
Wouldn't know and seems irrelevant to the debate without the weight of the train set.

Quote:
Originally Posted by elfabyanos View Post
4) The French AGV will have less potential traction motors because it has about half as many axles as a Shinkansen of equivalent length. So if space was a restriction on Shinkansens, all of a sudden the French have doubled the power output of their traction motors and still managed to find space under the car.
Again irrelevant without necessary figures to make full comparison.


Quote:
Originally Posted by elfabyanos View Post
5) As I said, space has been a restriction for Eurostar - they weren't able to fit the power required into the normal space in a locomotive. So space is a problem for both concepts, as I originally stated. All I am trying to point out is that it isn't a problem for just one of the concepts, and certainly not for the reasons you suggest.
And I have been saying from the beginning, "The trick is to balance weight and mass"

Quote:
Originally Posted by elfabyanos View Post
6) Traction motors aren't that big. Transformers and other electrics are.
See the traction motors here fitting snugly in the bogie - this isn't a tram, it's the bogie of a Union Pacific diesel freight locomotive!
Again irrelevant without necessary figures to make full comparison.

Quote:
Originally Posted by elfabyanos View Post
There is space to power a ten car train to 500mph - we just need to develop the technology.
Without further advancement in metallurgy for better magnetic induction, introduction of lighter stronger material such as carbon composite material, and aerodynamic design it is a pipe dream.
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Old February 7th, 2008, 04:48 PM   #4
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Quote:
Originally Posted by Tri-ring View Post
320 km/h/s (Design)
That's about 9G! Most of the passengers would pass out!
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Old February 7th, 2008, 10:42 PM   #5
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Quote:
Originally Posted by Tri-ring View Post
No, my point was that smaller motor will always have lower power ceilings which I have pointed out in my first post.
What relevence is that? Some trains have 12 motors, others have 64. Let's make one with 100. Let's make one with 10. So that's a power ceiling that's irrelevent to the debate by a factor of 5, if not 10. AND, that's assuming there is a power ceiling with motor design, which there isn't. Well, until you get to the planck constant, but even Hitachi and Alstom are still pretty far from dealing with quantum accuracy in their motor designs.

Quote:
I agree but the more motors you place weight gains exponentially, while power output will not.
What? No, if you add more motors, the weight gains linearly. If I put two motors of equal size on a vehicle, the weight is twice the weight of one motor. Not two squared or some such nonsense.

Quote:
Simply put if you have a single motor with 100 M of wire and compare it with two small motors that has 75 M of wire each, the strength may be stronger by 50% but the weight/power ratio will be offset due to the total weight of two motors.
And then you have to contain the extra power generated by the stronger motor, and strength in materials increases at the inverse square of the power forced through it, so, to make materials strong enough to contain the extra power you have to add a disproportionate amount of weight. Your theory on power to weight ratio is shot to pieces - but it's not even relevant anyway - more on that later.

Quote:
This means double the motors does not always add up to double efficiency as you postulate because you need to apply additional weight to compensate for additional mechanism needed for mounting, gearing and so on meaning power/weight ratio will only be marginal.
You're on your own planet mate - where did I "postulate" that double the motors equals double the efficiency? Your reading what you want to read and not paying attention to what I'm REALLY saying. I think you probably completely misunderstood a previous comment I made on impedance, because you have no understanding of electrical resistance. If I have to explain to you what impedance is, and that it is utterly nothing to do with efficiency, I'm going to shoot myself.

Quote:
Never said that knowing that Shinkansen motors lies beneath the boogies but if you compare a locomotive type and a distributed power system that is both able to obtain 300Km/h commercial speed then the locomotive system will always be faster at minimum setting.
What on earth are you saying? That when at minimum setting, which presumably is at rest because surely the most minimum power setting is no power i.e. 0 km/h, one is faster than the other!? Please rephrase your point so that I can understand what your saying.

Quote:
Wouldn't know and seems irrelevant to the debate without the weight of the train set.
Well, the point was to illustrate that in the space available they put a comparable amount of power to a high speed train without even trying to make it high powered - because that was your point - about the space it takes up (BTW an Electrostar is a 100mph distributed power commuter electrical multiple unit). The weight of the train doesn't change how much space it takes up. Well, it does, but it has to weigh a lot to have measurable difference - like the weight of a star perhaps. But, again I'm sure Einstein's general theory of relativity didn't factor into your thoughts either.

Now, I'm about to give you an important lesson in speed. And this derives directly from Newton. It's concerned with the preservation of momentum.

Does power to weight ratio affect accelration?

Ans: Yes.


Does power to weight ratio affect top speed?

Ans: No, not really.

At a constant speed absolutely none of the power of the motor goes into maintaining the momentum of the mass (i.e. weight as you put it) of the vehicle. ALL of the power is spent on overcoming friction.

If you want proof have a look at the various performances of cars with the same engines in them. The easiest way to see this is in car magazines with tables and tables of all the current production models in the back. I believe WhatCar in the UK is a good one. Now, you'll see from the performances of the cars, those with the same engines such as an Audi TT and an Audi saloon, have a similar top speed for the same engine, but vastly different 0-60 times due to their weight differences. (Caveat - obviously manufacturers change lots of other things too such as gearing ratios so it's only a rough guide to this phenomenon).

So no, it's not irrelevant without knowing the weight of the vehicle. Which for an Electrostar would be 865 tons for a 5 unit train if you'd have bothered to explore that link I posted. http://www.therailwaycentre.com/New%...a/EMU_375.html

But that wasn't my point was it? Do you get my point yet? Where have we been here before - Oh yes, on that mind-numbing discussion about cornering momentum during which you also proved you'd never ever turned up for a physics lesson at school.

Quote:
Again irrelevant without necessary figures to make full comparison.
If your looking at the intended point then you can use the necessary figures (PROVIDED) to make the deductions relevant to the assertion.

64 motors, therefore on 64 axles, to get 300 km/h out of the train. As the French train uses shared bogies The French must be using a proportionately more powerful motor (for which they have found space to put it in) to power their train. I'm not even saying they needed to, but they managed to put much more powerful motors in a distributed power design. Where is the "theoretical ceiling" then? And whence shall we arrive at it? None of the evidence so far suggests your "theoretical ceiling".

Quote:
And I have been saying from the beginning, "The trick is to balance weight and mass"
HAhahahahahaHAHAHAHAH!!!!!! So you can control the force of gravity can you!

Physics lesson number two - Weight is the force of gravity multiplied by mass. If you want to "balance" the weight to be lower in proportion to the mass, maybe you can take the vehicle to the moon, or Mars. Hell, why not get rid of the weight altogether and blast the damn thing into space!!!!

Quote:
Without further advancement in metallurgy for better magnetic induction, introduction of lighter stronger material such as carbon composite material, and aerodynamic design it is a pipe dream.
You see here you actually sound like you might know what you're talking about, but I know you haven't got the foggyest, they're just fancy words you like to string together to sound clever. If you went to any of the technical design sessions at Alstom, you would be completely and utterly lost as to what the engineers were talking about from beggining to end. I absolutely cannot wait to see what nonsense you come up with next.

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Old February 8th, 2008, 04:21 AM   #6
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French TGV have 4x1,1MW motors in their cars (some have 2x1,1MW motor at each outermost bogie in the coaches)

Siemens Locomotives like Taurus have 4x 1,6MW motors .. .these can easily be fitted in any HST.

Available Power Output is not the limiting factor here.
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Old February 8th, 2008, 11:38 PM   #7
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Quote:
Originally Posted by Tri-ring View Post
Next let's look at specs for the two trains.

British Rail Class 373 (Eurostar)
Formation 20 cars (Three Capitals)
Car body Steel
Weight 752 t (Three Capitals, empty)
Power output 12.2 MW 25 kV
Voltage 25 kV, 50 Hz AC
Maximum speed 334.7 km/h (Record)
300 km/h (Service)
€* is underpowered.
It is due to safety special specifications: €* is the only HST allowed to cross Chanel tunnel with passengers onboard.
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Old February 9th, 2008, 03:15 AM   #8
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Quote:
Originally Posted by elfabyanos View Post
What relevence is that? Some trains have 12 motors, others have 64. Let's make one with 100. Let's make one with 10. So ...
...
...
Could you summarize, seriously I really can't understand.
The reason I wrote irrelevant is because it does not have any figures for comparison. Without it it is completely out of context.
And really can you cut the sarcasm it really does nothing to create an arguement.
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Old February 9th, 2008, 12:12 PM   #9
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Nope.
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Old February 9th, 2008, 03:58 PM   #10
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I remember being taught in grade school that not being able to summarize a question at hand is because you really do not understand what you want to ask.
I am guessing that that is the case.
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Old February 9th, 2008, 08:38 PM   #11
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Ok then.

Your point = power ceiling exists due to size of motors.
My point = there's loads of space for big motors, so it doesn't matter.

GWTFP.
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Old February 10th, 2008, 05:11 AM   #12
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Yes there maybe room for bigger motors but there will always be a tradeoff.

Japan's Shinkansen places a motor on each axle and do not relay power to other axles so it requires minimum gear mechanism, they simply use various sensing mechanism and slow the motor directly by lowering the electric feed to each motor to gain best result.

If you look at the diagram of the new French AGV below, you'll see that it has a fairly large motor under the cabin and I assume power is relayed to the 6 axles via power shaft meaning it requires further mechanisms such as transmission gear box, traction control gears and so on which becomes additional weight.(I think it is represented in orange)



Space will always be a premium for any type of transportation vehicle and it has always been the design engineer's main theme to cope with this problem, but at the end they will need to wait for new material and/or new technology to be developed when they hit a potential ceiling.
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Old February 10th, 2008, 02:01 PM   #13
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But you're making massive assumptions.

Why assume that all the axles are driven?

Here's athe block diagram of the Pendolino, Alstom's currently proven decades old technology



I'm not quite sure where the 9th car has gone, it's supposed to be the class 390 from this Alstom document http://www.theiet.org/events/2007/pr...s.cfm?type=pdf

but regardless it can be seen that only 12 axles are driven. No need for complicated and wasteful mechanical power transfers. If you can find an example of mechanical power transfer in an electric passenger train anywhere in the world I would be most interested and fascinated.

It seems that the "bloc traction" in the AGV diagram is not the traction motor, but the converter/inverter that drives the 3-phase traction motors, motors that would be mounted directly onto the axles. In the Pendolino it's the 4 quadrant converter 3 phase inverter that takes up this position on the vehicle.

As a side I would expect the transformers, converters and inverters to be much larger that the motors, given the astronomical voltages used to reduce losses in the overhead cables.

I see no reason to believe that Alstom have changed their approach for the AGV, when they already have a highly successful high speed (ish) distributed power format format in the Pendolino franchise. There is no need to drive all of the axles. Over half the axles are undriven. Presumably undriven axles could be driven too - so if ever needed this would be an obvious solution to a requirement of doubling the power should it arise.

Quote:
they simply use various sensing mechanism and slow the motor directly by lowering the electric feed to each motor to gain best result.
I'm not sure where you're going with this - all new high speed trains use various sensing methods and slow the motor directly by lowering the electric feed. In fact all electric trains.

Quote:
If you look at the diagram of the new French AGV below, you'll see that it has a fairly large motor under the cabin and I assume power is relayed to the 6 axles via power shaft meaning it requires further mechanisms such as transmission gear box, traction control gears and so on which becomes additional weight.(I think it is represented in orange
The orange is the step-down transformer. Motors need high current-low voltage to give good tractive effort to drive the vehicle, but thin overhead cables need high voltage-low current to avoid transfer losses in distribution. I believe it is dangerous to make such assumptions, as it leads one on a wild goose chase.

Quote:
Space will always be a premium for any type of transportation vehicle and it has always been the design engineer's main theme to cope with this problem, but at the end they will need to wait for new material and/or new technology to be developed when they hit a potential ceiling.
Apart from this being obvious to almost any profession or human endeavour, there isn't a specific ceiling anywhere in your musings that you can claim.
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Old February 10th, 2008, 05:03 PM   #14
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Why do you assume the "bloc traction" in the AGV diagram are not traction motor?
In the TGV diagram it shares the same definition, and I am quite sure that that points to the motor. The orange maybe a step down transformer as you state but I do not see the reason why they will divide converters from the transformer in such a simple diagram without pointing out the motor.

Utilization of a gear box is common in any type of axle driven transportation. When the diameter of an axle differs from the diameter of the power shaft you relay power using a gear box, it is no different whether it be internal combustion or electric. You also need one if the motor is positioned perpendicular from the axle.
As for the Pendolino, if the motors can be reduced in size and still maintain power then why didn't they power both two axles in one boggy instead of just one or change the motors to go faster?

There are ceilings within any given technolgy. The only way to break that ceiling is to induce another technology, whether it be metallurgy for stronger magnetic strength, lighter composite material, design concept and/or a whole new technolgy all together which you seem do not accept. It's called pushing the envelope and if there wasn't a ceiling then there would be no reason for research and development, would there.

My point is metallurgy for stronger magnetic strength is becoming a bottleneck and without a breakthrough, the electric motor for a given mass at a given current may reach it's potential hieghts soon.
You can turn up the voltage to the overheads but the motor does not respond in a linear way and there is a maxout ceiling for electric motors where it will not increase output no matter how much you increase voltage.
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Old February 10th, 2008, 08:43 PM   #15
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Quote:
Originally Posted by Tri-ring View Post
Why do you assume the "bloc traction" in the AGV diagram are not traction motor?
In the TGV diagram it shares the same definition, and I am quite sure that that points to the motor. The orange maybe a step down transformer as you state but I do not see the reason why they will divide converters from the transformer in such a simple diagram without pointing out the motor.
Because on the AGV the traction motor would be in the middle of the car. The power would then need to be distributed to the bogie which swivels in relation to the car and transferring that power would be a nightmare. Think about it.

Quote:
Utilization of a gear box is common in any type of axle driven transportation. When the diameter of an axle differs from the diameter of the power shaft you relay power using a gear box, it is no different whether it be internal combustion or electric. You also need one if the motor is positioned perpendicular from the axle.
Your idea of transferring power from areas distant to the axle, or powering multiple axles, requires a power shaft, not a gearbox. So we're not discussing gearboxes, in fact, I havn't mentioned gearboxes once have I?

Quote:
As for the Pendolino, if the motors can be reduced in size and still maintain power then why didn't they power both two axles in one boggy instead of just one or change the motors to go faster?
The motors weren't reduced in size - they are already small.

They didn't power both axles because they didn't need to.

The motors were small and powerful enough to only need to power 12 axles to propel the train to 225km/h - DID YOU NOT READ THE LINK? Have you looked at the block diagram above? Can you not see the black circles at the bottom are motors? Can you not see in the key at the bottom that the black circles are entitled "motored axle"? Are you being purposely obtuse?

Quote:
There are ceilings within any given technolgy. The only way to break that ceiling is to induce another technology, whether it be metallurgy for stronger magnetic strength, lighter composite material, design concept and/or a whole new technolgy all together which you seem do not accept. It's called pushing the envelope and if there wasn't a ceiling then there would be no reason for research and development, would there.

My point is metallurgy for stronger magnetic strength is becoming a bottleneck and without a breakthrough, the electric motor for a given mass at a given current may reach it's potential hieghts soon.
Are you never going to get my point? We can push the envelope when it's needed, right now it's not the motors. This you don't seem to accept. Otherwise what you say is perfectly true.

The problem for engineers at the moment is not power output, it's power consumption.

Quote:
You can turn up the voltage to the overheads but the motor does not respond in a linear way and there is a maxout ceiling for electric motors where it will not increase output no matter how much you increase voltage.
Again another priceless piece of bullshit. Turn up the voltage? What? Do you know what a transformer is? Do you know what a 3-phase inverter is?

Basically, when I described what a step down transformer is you had no idea what I saying. I will explain again - you better understand this time or there is no hope for you. The transformer is required because of the high voltage. This is to make the transmission of the power from power station to train more efficient. It has ABSOLUTELY NO EFFECT ON THE PERFORMANCE OF THE VEHICLE. If you turn up the voltage on the overhead cable what will happen is that none of your trains will work any more until you replace their transformers with ones that match the new power voltage. Once you've done that the train will perform EXACTLY as it did before, but your power station won't have to work as hard to transmit the power to the train.

The voltage going to the motors is controlled by the 3-phase inverter.

Your point about metallurgy may be true - new materials are needed once the limits of the ones available have been reached. But you cannot see that this is irrelevant - the motors available are plenty powerful for a 400 km/h distributed power high speed train (which the Siemens Velaro is, the Fastech 360 and AGV will be) - they can/will be able to hit that speed, the problem is doing it economically. As I said it's power consumption which is the problem. 500km/h is not a pipe dream. If you powered all the axles in the AGV it would probably be able to hit 500km/h. But where to put all the required electrics? And who's going to pay the electricity bill? That's the barrier.

Is there anything I can say that will make you realise that I actually know a thing or two more than you? I don't feel proud of that - it's not lost on me that I'm actually wasting so much of my time responding to you, but I'm dumbstruck by your inability comprehend my very salient and logical points, and that goes for your responses to other people on this forum too. There are loads of things I've pointed out to you that you haven't acknowledged and I'm assuming that's because you realised you didn't actually know.

Last edited by elfabyanos; February 10th, 2008 at 08:51 PM.
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Old February 10th, 2008, 11:46 PM   #16
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Regarding our previous silly conversation about cornering, from http://xzellent.wordpress.com/tilting-bogie-design/:

Quote:
Aeroplanes and bicycles simply tilt in place; but automobiles and railway trains cannot do this on their own. To make their turns easier, the roadway of a high-speed highway or railway is canted inward around the curve. To a passenger in such a vehicle, the outward centrifugal force is countered by an inward gravitational one, thus removing the discomfort. (It should be noted that vehicles with high centers of gravity rounding very sharp curves at very high speeds may in fact topple over altogether; banking would also be the answer to counteract this threat. However, since passenger comfort becomes an issue at much lower speeds and gentler curves, railway designers, having kept their passengers comfortable, do not need to worry about trains overturning).
Here's a picture of the alstom motor in the Czech pendolino from this site http://spz.logout.cz/vozidla/680/680_cd.html. It's not too big.



The motor on the old Fiat Pendolinos was under the body, connected by a shaft to transfer power. I haven't ascertained if this is still the design used. http://www.memagazine.org/backissues...g/tilting.html

It also has a small section regarding cornering
Quote:
Fiat engineers designed the Pendolino active tilting system to automatically lean the body shell of passenger cars by a maximum 8 degrees toward the inside of curves, so the Pendolino can compensate up to 1.35 meters per square second of the centrifugal acceleration felt by passengers. This permits a Pendolino to run with accelerations of 1.8 to 2 meters per square second and still remain well within the limits of comfort, determined by railway engineers to be 0.8 to 1 meters per square second. As a result, the train can negotiate curves at up to full speed, which is 35 to 45 percent faster than conventional trains without any effect on the quality of the ride.

Last edited by elfabyanos; February 11th, 2008 at 12:14 AM.
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Old February 11th, 2008, 12:20 AM   #17
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Some more random info on the pendolino for comparison from http://findarticles.com/p/articles/m...81006310/pg_3:

Maximum speed 225km/h
Power at rail 5.1MW
Starting effort 204kN
Traction Onix 800 IGBT
Inverter control Agate
Electrical supply 25kV 50Hz
Motored axles 12
Motors/inverter 2
Number of motor bogies 12
Number of trailer bogies 6
Bogie wheelbase 2.7m
Train weight 458 tonnes
Motor bogie axleload 14.7 tonnes
Trailer bogie axleload 13.8 tonnes
Unsprung mass/motor axle < 2 tonnes
Unsprung mass/trailer axle < 1.75 tonnes
Distance between bogie centres 17m
Braking Rheostatic and regenerative
Noise
Internal < 65dBA
External < 93dBA
Trailer car length 23m
Trailer car width 2.73m
Seating capacity
First class 145
Standard class 294
BRITISH PENDOLINO MAIN COMPONENTS SUPPLIERS


Again, to add weight to the space thing, the 5-car Super Voyager has 10 of the exact same Onix 800 traction motors as a Pendolino. It also is distributed power, and has tilt technology. Somehow though, they manage to find space to put in 5 750hp diesel engines to power the electric motors. The space is saved by taking away the transformers and other ac power related electrics.

http://www.therailwaycentre.com/New%...U_220_221.html
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Old February 11th, 2008, 04:24 AM   #18
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As i wrote earlier, showing a motor is irrelevent.
If you going to place a picture of a motor I suggest showing one that is fitted in a boggie with the supplementary parts to relay power from the motor to the axle. Then we will be able to discuss with context.
As for the reduction I wrote IFthe motors can be reduced in size and still maintain power then why didn't they power both two axles in one boggy instead of just one or change the motors to go faster?
A reduction of size will reduce weight which will be benefitial to conserve energy.

Why do you always place assumption as if they are fact?
Quote:
They didn't power both axles because they didn't need to.
The motors were small and powerful enough to only need to power 12 axles to propel the train to 225km/h - DID YOU NOT READ THE LINK?
This is your assumption since it does not say anything about motor size requirements within the link. It only states that there are 12 powered axles.
If they were able to distribute power to both axle with minimum additional weight then I think they would since it would gain better traction minimizing loss in torque resulting to better acceleration which will reduce energy consumption.
As I have been saying from the start the trick is to balance weight with mass.

Quote:
The problem for engineers at the moment is not power output, it's power consumption.
Oh boy.
Power output and power consumption for electric motors are of the same problem like two sides of a coin.
Since we are using normal conductive material for coils, it has resistance. The more energy you put in more energy is lost through resistance which turns into heat.
There are various ways to bypass this problem;
1. Create a stronger magnet that can generate greater output within same power feed.
2. Create material with less resistance per unit sectional area.
3. Create material that does not lose coherent properties under high temperature.

Quote:
The transformer is required because of the high voltage. This is to make the transmission of the power from power station to train more efficient. It has ABSOLUTELY NO EFFECT ON THE PERFORMANCE OF THE VEHICLE. If you turn up the voltage on the overhead cable what will happen is that none of your trains will work any more until you replace their transformers with ones that match the new power voltage. Once you've done that the train will perform EXACTLY as it did before, but your power station won't have to work as hard to transmit the power to the train.
And you really do not understand electric circuitry, you gain performance through greater input of electricity becuase transformers does not adjust variably, they multiply adjusted on preset frequency.
What you are describing is overload shut down by a breaker to avoid overload to the motors and has nothing to do with transformers. A motor has a safety margin and will gain performance if given enough power up to it's designed limit.
That's how the TGV broke the speed record, remember?
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Old February 11th, 2008, 12:45 PM   #19
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Quote:
Originally Posted by Tri-ring View Post
This is your assumption since it does not say anything about motor size requirements within the link. It only states that there are 12 powered axles.
If they were able to distribute power to both axle with minimum additional weight then I think they would since it would gain better traction minimizing loss in torque resulting to better acceleration which will reduce energy consumption.
As I have been saying from the start the trick is to balance weight with mass.
It says "motored axle" on the diagram. If you follow the link it shows you a pretty picture too.

Yes, more axles driven would give better traction, but traction is not all that important for lightweight high speed passenger trains, friction is. This is why passenger locos tend to be of bo-bo design, but freight trains co-co. 12 axles driven is more than enough axles for a passenger train.

Want proof? The class 91 hauls 10 coaches to 225 km/h and that has maximum 4 powered axles.

BTW you sound so ridiculous when you say "balance the mass with weight" - weight is dictated by gravity, not the engineers at Alstom now matter how clever they are.

Quote:
Oh boy.
Power output and power consumption for electric motors are of the same problem like two sides of a coin.
Since we are using normal conductive material for coils, it has resistance. The more energy you put in more energy is lost through resistance which turns into heat.
There are various ways to bypass this problem;
1. Create a stronger magnet that can generate greater output within same power feed.
2. Create material with less resistance per unit sectional area.
3. Create material that does not lose coherent properties under high temperature.
No, they can build more powerful motors and fit them into the space available. They cannot justify the electricity costs. Now, you may have accidentally stumbled on to the actual ceiling, which is getting more power out of the motors for the same power input - i.e. making them more efficient. But that wouldn't be a revelation because that's what Alstom said in the flipping press release for the AGV. It has nothing to do with the size of the motor - as I said before some of the most efficient motors in the world are tiny. I understand how electric motors work, but I love your quirky slightly erroneous descriptions of technical things you do not fully understand.

Quote:
And you really do not understand electric circuitry, you gain performance through greater input of electricity becuase transformers does not adjust variably, they multiply adjusted on preset frequency.
What you are describing is overload shut down by a breaker to avoid overload to the motors and has nothing to do with transformers. A motor has a safety margin and will gain performance if given enough power up to it's designed limit.
That's how the TGV broke the speed record, remember?
Haha, you div. Transformers change the voltage idiot.

I only explained this to you because of some other nonsense about transformers you were going on about, and now you've just come up with a classic.

You said changing the voltage in the overhead wires would have no effect getting better performance out of the motors because the motors were at their theoretical maximum. I was trying to teach you that the motors do not see the voltage in the overhead wires at all so it's a blindingly obvious and pointless statement for you to make - because the o/h wires are behind a transformer, a converter and inverter in the circuit. But you didn't cotton on. Nevermind, it wasn't relevant to the discussion anyway, just thought you might like to learn something.

Then you say what I was talking about was overload to the motors? Haha! No it wasn't. If you up the voltage in the o/h wires the sensors in the transformer circuitry would shut the power. The breaker to protect the motors is entirely separate and unrelated.

The TGV broke the speed record by using distributed power for the special train

Any response to my posts about turning forces? Has that sunk in yet?
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Old February 11th, 2008, 02:09 PM   #20
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Quote:
Originally Posted by elfabyanos View Post
Haha, you div. Transformers change the voltage idiot.

I only explained this to you because of some other nonsense about transformers you were going on about, and now you've just come up with a classic.

You said changing the voltage in the overhead wires would have no effect getting better performance out of the motors because the motors were at their theoretical maximum. I was trying to teach you that the motors do not see the voltage in the overhead wires at all so it's a blindingly obvious and pointless statement for you to make - because the o/h wires are behind a transformer, a converter and inverter in the circuit. But you didn't cotton on. Nevermind, it wasn't relevant to the discussion anyway, just thought you might like to learn something.

Then you say what I was talking about was overload to the motors? Haha! No it wasn't. If you up the voltage in the o/h wires the sensors in the transformer circuitry would shut the power. The breaker to protect the motors is entirely separate and unrelated.
You obviously do not know how a transformer works, do you.
It's basically two coils wrapped near one another and magnetic induction relays an electric current from one coil to the other.
Changing of voltage occurs through the differencial of amount of one coil to the other.

Here is a excerpt form wiki for reference.

Quote:
A changing current in the first circuit (the primary) creates a changing magnetic field; in turn, this magnetic field induces a changing voltage in the second circuit (the secondary). By adding a load to the secondary circuit, one can make current flow in the transformer, thus transferring energy from one circuit to the other.The secondary induced voltage VS is scaled from the primary VP by a factor ideally equal to the ratio of the number of turns of wire in their respective windings:


So it is in a preset multiplication state in relation with the number of winding from one coil with the other.
GET IT?
If there is a sensor it is a breaker unit since basically a transformer circuit is just a set of coils.
Try understanding fundemental electrodynamic. It's usually taught at high school. (In my country anyways)
By the way the 3-phase inverter act as the throttle to power up and/or down the motor. So it will also be affected if the overall power input is turned up as well and will not cut off extra power unless again there is a breaker unit.


Quote:
Originally Posted by elfabyanos View Post
No, they can build more powerful motors and fit them into the space available. They cannot justify the electricity costs. Now, you may have accidentally stumbled on to the actual ceiling, which is getting more power out of the motors for the same power input - i.e. making them more efficient. But that wouldn't be a revelation because that's what Alstom said in the flipping press release for the AGV. It has nothing to do with the size of the motor - as I said before some of the most efficient motors in the world are tiny. I understand how electric motors work, but I love your quirky slightly erroneous descriptions of technical things you do not fully understand.
What did Astrom actually say?
Effciency and overall maximum power output has nothing to do with one or the other.
Effciency means conversion rate of a given input/output ratio.
Overall maximum power output is just that.
Potential output ceiling is a complete different issue all together.
Again another baseless assumption.

First, weight can differ with the same mass through difference in material.
Second you need to understand the neccesity of supplementary equipment that may or may not accompany with the main motor.
Third and foremost the juggling act of balacing weight with mass to gain optimum performance.
That is what "the trick is to balance weight with mass" means.

As for, "The TGV broke the speed record by using distributed power for the special train"

I think alot of people will tell you differently.


One last word, CUT THE CUSSING, it is annoying and really has no use in creating an arguement.
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