Question:
What about putting a dynamo at the front of a train?
Richie D
2006-09-13 09:32:32 UTC
this would then use the wind to turn a fan,producing electricity for say the lights or other electrical appliances.
Eighteen answers:
anonymous
2006-09-13 09:34:26 UTC
Brilliant... and the wind resistance caused by the fan would slow the train down so that it would need more energy to move it along.



In fact, as using a fan to generate electricity is likely to be quite inefficient I would expect that the train would actually need more energy to push the fan along and generate the electricity than it would use just to generate the electricity direct in the normal way.



So what you've just invented is a way of WASTING energy. And of course, as soon as the train stopped at a station all the lights would go out...
scuba_shah
2006-09-13 09:58:12 UTC
There is no free ride in this world.

What you are proposing is a very inefficient transfer of energy.



To move a train Air resistance, Friction and Gravitational forces need to be overcome. This is done using the Train Motor/Engine, which uses Gas, Electricity or what ever to run.



By placing a dynamo with a Fan in front of a train you are increasing the coefficient of the drag for the train, hence more energy is needed to push the train forward.



The only time such idea makes since is when train is slow down. Instead of using a break, transferring kinetic Energy to Heat, dynamo can be used to transferring kinetic Energy to Static energy for a later use.
CTM
2006-09-13 09:38:51 UTC
Good Idea. A train has a lot of weight behind it so maybe instead of using the wind maybe wait until the train is up to speed and then make a connection to a wheel to turn a gear because with all that weight it will not effect the train and then the energy can be geared to make the final output very fast for Elec. Power generation.



Remember when a train hits a vehicle in an accident that sometimes it takes up to a mile to get the train stopped. That shows how much energy has been built up to due the weight of the train.



At the very least use this gear setup on several of the back train cars as a braking system and while they are turning under a heavy gear ratio they help slow the train when it is time to stop the train and then the gears are connected to a generator setup and Elec. Power is stored for later use.

Good Idea !!
james
2006-09-13 14:36:24 UTC
first of all, this requires the train to be in motion unless it is a windy day. secondly, the power out put of 1 fan isnt cost effective, you pay for the systems to run off 1 fan to power 1 or 2 light bulbs, that might work but any more would need alot more fans and generators.
anonymous
2006-09-13 09:37:42 UTC
In essence, the engine will power this anyway, as the dynamo would need friction to power it, and the friction would require concomitantly greater engine power to generate the power, so there would be some losses in heat. It's all about the Second Law of Thermodynamics ... that's why perpetual motion machines could never work ...
Dave_Stark
2006-09-13 09:36:23 UTC
Interesting idea -- but wouldn't wind resistance increase, thereby requiring more power to propel the train, thereby negating any expected energy savings?



Simpler to just tap power from the engine itself to power the rest of the train, or tap into the electrical power of an electric train.
DanE
2006-09-13 09:34:47 UTC
Perpetual motion refers to a condition in which an object moves forever without being driven by an external source of energy.



The term is commonly used to refer to machines which display this phenomenon. In the macroscopic world, perpetual motion is not generally considered to be possible. Perpetual motion machines (the Latin term perpetuum mobile is not uncommon) are a class of hypothetical machines which would produce useful energy in a way which would violate the established laws of physics. No genuine perpetual motion machine currently exists, and according to certain fundamental laws in physics they cannot exist. Specifically, perpetual motion machines would violate either the first or second laws of thermodynamics. Perpetual motion machines are divided into two subcategories (some physicists, including the noted professor of thermodynamics Mark W. Zemansky, include a third), defined by which law of thermodynamics would have to be broken in order for the device to be a true perpetual motion machine.
Joseph G
2006-09-13 18:21:35 UTC
For emergency use, airplanes often have small wind driven electric generators or hydraulic pumps that pop out when the engine stops.
J B
2006-09-17 08:30:06 UTC
you would waste energy on moving the train. But if you put the fans in cones with the pointey bit chopped off and moulded them in perfectly smoothly it works.*

* You would have to have a battery to avoid power cutting out at stations.
slatibartfast
2006-09-13 19:01:55 UTC
Better to generate from wasted energy like a linear generator on the suspension. Would be a good idea for cars actually.
hoarp001
2006-09-13 13:24:12 UTC
You would be better off mounting a rubber tyre to run along the rails to gerate electricity with a big gearbox....
stafflers.t21@btinternet.com
2006-09-13 09:36:29 UTC
Because the people who control the power won't invest in renewable sources of energy.



They could also put generators on the wheels.



If the electricity companies and governments really cared for renewable energy they would put serious heavy duty solar panels on everybodies' house, and a wind turbine on their walls.



But they don't.
UNIQUE KID
2006-09-13 14:32:16 UTC
oh ya good idea but it will be hard for the train to stop in emergency.Fist you have think about health and safety.
anonymous
2006-09-13 09:38:06 UTC
It is a really good idea, but I'm sure if it was practical it would have been tried already.
Bear Naked
2006-09-13 09:35:24 UTC
Would this be different from the little propeller at the caboose?
anonymous
2006-09-13 09:40:44 UTC
ill get one off my bike
russellhamuk
2006-09-13 09:38:17 UTC
why make it go faster
anonymous
2006-09-13 09:34:16 UTC
OOH! YAH! Can I help you with this project? Please?


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