Understanding the Electric Car Motor

Written by Akweli Parker from HowStuffWorks.com.

After many false starts and a lot of -- forgive the expression -- resistance from major automakers, it appears as if mass-produced electric automobiles are ready to make significant inroads on the roadways.

But with the internal combustion engine claiming nearly a century of market dominance, much of the driving public is clueless about how electric motors operate -- are they complicated? Are they safe? Thus, we present this brief guide to Understanding the Electric Car Motor.

Electric Car Motor Parts

Electric car motors work pretty much like any other electric motor. The motor itself consists of a field magnet, with north and south poles, an armature, commutator, and brushes (and very often, no brushes, as brushless motors last longer). A battery or set of batteries, when connected, turn the motor into an electromagnet.

In addition, a controller is a computerized device that allows you to determine the rate and level of energy application, similar in effect to a throttle on a gasoline engine.

How the Parts Work

Two stationary, oppositely charged magnets sit in a steel drum -- this is the field magnet. The armature, which consists of wound wiring, a commutator, and (sometimes) brushes, sits on an axle within the drum assembly. As an electrical charge is sent through the armature, it becomes an electromagnet, and spins as its ends are repelled and attracted to the poles of the field magnet. To keep this rotation going, the polarity of the charge must be reversed. In a motor with brushes, the brushes accomplish this. In a brushless motor, the parts are laid out somewhat differently and a computer controls the action.

The bottom line is that this assembly rotates about an axle at very high RPM and can be hooked up to power the wheels of an automobile.

As you can perhaps tell, electric car motors are considerably simpler than their internal combustion counterparts. There is no need for fuel lines or tanks or an exhaust system in a completely electric vehicle. And since there are so few moving parts compared to an internal combustion engine, electrics are highly efficient users of energy.

It's estimated that electric motors are able to convert about 80 percent of the energy they generate into usable forward motion. Gasoline engines typically only muster 15 percent efficiency. Where does that power go? It gets lost in the myriad movements of a gasoline engine's parts and in idling, according to the Environmental Protection Agency.

Electric cars used to be the pre-dominant vehicles on the roads -- back in the early 1900s, before they were elbowed out by the internal combustion engine. They've been dismissed by major automakers throughout the decades. But with worries about emissions mounting and of fossil fuels running out, it may very well be their time once again.

 

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Hydrogen Fuel Cell vs. Cars Electric Cars

Written by Christopher Lampton from HowStuffWorks.com.

Most people know by now what an electric car is. It?s a car that runs on a battery-powered electric motor. Unlike most cars on the road today, it lacks an internal combustion engine and uses electricity as its fuel rather than gasoline. Because it doesn?t burn fossil fuels to make itself run, it doesn?t produce any pollution while it?s in operation. This, at least in theory, makes electric cars a very green form of transportation.

But what in the world is a hydrogen fuel cell car? It?s also a kind of electric car. It runs on a motor powered by electricity. What makes it different from a battery-electric vehicle (or BEV) is where the electricity comes from. Instead of a battery, a hydrogen fuel cell car has, well, a hydrogen fuel cell. This is a device that takes hydrogen, the most abundant element in the universe, and generates electricity from it while the car is running. In effect, a hydrogen fuel cell is a kind of battery that makes electricity on the fly.

Drive 100 Miles for 1 Dollar of Electricity

To see how this works, let?s take a quick refresher course in high school chemistry. (Don?t worry; we?ll make this as painless as possible.) Hydrogen is the smallest, lightest atom in existence. A standard-issue hydrogen atom consists of two things: a proton (which has a positive electric charge) and an electron (which has a negative electric charge). The hydrogen fuel cell strips these two things apart, so that the electrons are free to go their own way and become the electricity that runs the car?s motor. (Electricity Is nothing more a continuous flow of electrons.) Meanwhile, the proton becomes a hydrogen ion -- that is, a hydrogen atom with a positive electric charge -- and will bond together with any oxygen atoms in the vicinity to form water. (Water ? or H2O as the chemistry geeks call it ? is nothing more than two hydrogen ions with an oxygen atom attached.) This process releases a lot of heat, so the water becomes steam and the steam becomes the exhaust of the hydrogen fuel cell.

The great thing ? and the green thing ? about both electric cars and hydrogen fuel cell cars is that they don?t produce any pollution at the tailpipe (unless you consider the steam being produced by the hydrogen fuel cell to be a form of pollution). So no matter whether you decide to buy an electric car or a hydrogen fuel cell car (though the latter isn?t likely to be widely available to customers for quite a few years yet), you?ll be helping to save the earth?s atmosphere, right?

Well, not exactly. While neither type of car produces pollution at the tailpipe, they both have the potential to produce pollution when their ?fuel? is created. The fuel that an electric car runs on is electricity (which is used to charge the batteries) and the fuel that a hydrogen fuel cell car runs on is hydrogen (which is used to generate electricity). That electricity and that hydrogen have to come from somewhere. The electricity will mostly come from power plants that in the majority of cases are burning fossil fuels to produce that electricity and those fossil fuels will cause the same pollution that the electric car is intended to avoid. The hydrogen for the fuel cell vehicle will most likely be produced in the future by electrolysis, which involves passing electricity through water. And that electricity will come from the same potentially polluting sources as the electricity used to charge the electric car?s batteries.

The truth is, electric cars and hydrogen fuel cell cars both have the potential to be wonderfully non-polluting forms of transportation, but to make them truly green we?ll need to move away from methods of producing electricity that burn fossil fuels. Instead of burning coal to generate electricity, we?ll need to concentrate on environmentally clean methods like hydropower, solar power, wind power and nuclear power, which produce little or no polluting emissions. When the day comes that most of our electricity comes from these sources, the electric car and the hydrogen fuel cell car will both be nearly perfect forms of green, non-polluting transportation.

 

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