What about putting a dynamo at the front of a train?

Question

this would then use the wind to turn a fan,producing electricity for say the lights or other electrical appliances.

Answer 1

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...

Answer 2

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.

Answer 3

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 !!

Answer 4

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.

Answer 5

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 ...

Answer 6

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.

Answer 7

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.

Answer 8

For emergency use, airplanes often have small wind driven electric generators or hydraulic pumps that pop out when the engine stops.

Answer 9

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.

Answer 10

Better to generate from wasted energy like a linear generator on the suspension. Would be a good idea for cars actually.