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Rudi Kiefer: The pros, cons of electric motors
Rudi Kiefer
Car and motorcycle enthusiasts alike will agree that there’s such a thing as a “beautiful engine.”

Just look at Harley-Davidson’s most recent 2-wheel, 2-cylinder creations with their flowing curves, flawless chrome and rich powdercoating. Open the hood of an electric car, and you’ll find a whole lot of technical jumble. There’s no engine. Electric vehicles are powered by motors. To a classic car collector an electric motor will only have a “blah” appearance.

When it comes to performance, though, electric cars and bikes rule. An electric motor packs an enormous punch from the very first rotation. Due to the fact that electric motors produce no emissions, it’s likely that they will make gasoline engines obsolete within the next few decades.

But electric vehicles don’t come without environmental problems of their own. Electricity has to be produced to power their batteries. Coal, a heavy polluter, still accounts for 25 percent of power generation in Georgia, according to the U.S. Energy Information Administration (www.eia.gov).

Besides power generation, another problem lies in the construction of electric motors themselves. Two types prevail: the AC induction motor, and the brushless DC motor using permanent magnets. Every electric motor runs by working one magnetic field against another, which creates a pushing force. Induction motors produce magnetism in an outer coil called the stator.

This generates an electric current in an inner coil called the rotor, resulting in another magnetic field. The flow of the current now makes the rotor turn. This works well, but it requires more energy than a brushless DC motor, which uses permanent magnets. So-called rare earth elements such as neodymium, lanthanum and cerium are needed to build the most powerful magnets. Unfortunately, mining these minerals has already resulted in significant pollution. In China, the world’s main supplier of rare earth minerals, reports show severe contamination of soil and water, and increases in the occurrence of cancer.

Rare earth magnets are great for electric vehicles because they produce a lot of power with less weight than induction motors. But the environmental as well as dollar cost of rare earth extraction has risen sharply, driving prices up. Automakers are currently working on new magnet designs using less rare earth and more efficiency. What drives our vehicles will never have a “beautiful engine” again, but we can look forward to lots of power, and hopefully reduced pollution.
 

Rudi Kiefer, Ph.D., is a professor at Brenau University, teaching physical and health sciences on Brenau’s Georgia campuses and in China. His column appears Sundays and at gainesvilletimes.com.

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