Attaching a Generator to a Motor or Wheel
Many people believe they've discovered the way to fix all energy and transportation problems.
Their answer? Power an electric generator with an electric motor that are wired together!
The problem is, this simply does not work, even if a battery system is introduced,
nothing will cause the motor to infinitely turn the generator.
Why you say? Well it's basic laws of physics.
Read the Wikipedia article on
Perpetual Motion for more on the physics:
http://en.wikipedia.org/wiki/Perpetual_motion
You can never have an electrical or mechanical or thermal system which is more than 100% efficient, in fact, to date, you can not even have a system which is 100% efficient.
The energy inside of any closed system
will find some way of escaping as another form of energy.
For example, electrical energy will escape a closed loop of wire (or a motor attached to a generator) by either turning into Magnetic energy or Heat energy from the electrical resistance.
This means you'd have to find some way of keeping the energy from converting into another form of energy inside your closed loop to have a 100% efficient system.
Even if you do achieve this 100% efficient system, there is still absolutely no way you can create more energy from this system, the energy must come from somewhere.
If you must completely isolate your closed system from everything to reach 100% efficiency, how would more energy find it's way into your 100% closed system?
Some people believe that Fusion power plants are
Perpetual Motion machines, but unfortunately they are not.
In order for a Fusion Generator to run, you must keep introducing more Matter to convert into Energy, meaning you are not getting more power out of the system without placing some kind of fuel into it first.
In conclusion, there is no such thing as infinite energy system.
If some of this article boggles your mind, you may want to step back for a few minutes and read it again later.
Adding a Wind Generator to the Car
Another proposition given out has been adding a wind generator to the outside of the car. The idea being at high speeds the wind generator can generate electricity to power the car. This is also impossible. Here are a few examples why it won't work...
Let's say it takes 10,000 Watts to keep your car at 50 mph. And we're striving to maintain speed.
First example...
Say you put the wind generator attached to the outside of the car. Wind generators work by creating drag on free flowing air to convert the wind energy into rotational then into electrical. Thus the wind generator can't produce any more energy than the drag it creates on the air. So if you installed a 100% efficiency 1,000 Watt wind generator on your car, your car will then need 11,000 Watts of power to maintain speed. Your wind generator is supplying 1,000 Watts of that, so you're back to 10,000 Watts to maintain speed. Hence without even looking at efficiency losses, there is no gain.
Second example, slightly more complex...
Your car needs the 10,000 Watts to maintain speed because of the drag on the body and wheel friction. We'll just look at the drag on the body as at high speeds it is much larger than the wheel friction. Now imagine you removed the radiator under the hood as you don't need it for your electric car. Reason stands you could duct the air from your car's grill into a wind generator where your radiator once was.
Let's assume again everything is 100% efficient. The car is already suffering from drag because of the air being stopped under the hood so we'll say drag is the same with the wind generator, 10,000 Watts. Let's imagine you can fit a 1,000 Watt generator underneath the hood driven purely by the frontal area of the grill. With everything perfectly efficient, you will deliver 1,000 Watts additional to your motor, effectively decreasing your energy needs down to 9,000 Watts.
Sounds good right? Well in actuality there are inefficiencies. 95% loss from motor, 95% loss from controllers, 95% loss from transmission. 1,000 * .95 * .95 * .95 = 857 Watts. So now 10,000 - 857 = 9,143 Watts. Still better than nothing.
Now let's approach this differently. Instead of trying to harness the drag we're creating, let's try to get rid of it. Buy a $20 sheet of aluminum and place it over your grill. Your drag has reduced by 1,000 Watts, meaning your car only need 9,000 Watts to maintain speed. Much easier, simpler, and cheaper than a complex ducting/generator system.
Third example...
We've been assuming no external wind. Say like your car was parked with your wind generator running. It would generate power from the external wind and store it into the battery. You then bring in the generator to remove the drag and begin driving. That is completely doable and why many people install wind generators at their house (it'd be a pain in the butt to haul it around in the car).
Fourth example...
Given that the car needs 10kW to move at 50MPH, how big will the turbine be? Well, the
Skystream 2.4kW turbine has a rotor width of 12ft (4m), and weighs 170lbs (77kgs). To get 10kW, you'll need 4-5 of these.