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 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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