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Hoyi asked in 科學及數學其他 - 科學 · 1 decade ago

How does an electric motor work?

How does an electric motor work?

1 Answer

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  • 1 decade ago
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    An electric motor uses the attractive and repulsiveforces between magnetic poles to twist a rotating object (the rotor)around in a circle. Both the rotor and the stationary structure (thestator) are magnetic and their magnetic poles are initially arranged sothat the rotor must turn in a particular direction in order to bringits north poles closer to the stator's south poles and vice versa. Therotor thus experiences a twist (what physicists call a torque) and itundergoes an angular acceleration--it begins to rotate. But the magnetsof the rotor and stator aren't all permanent magnets. At least some ofthe magnets are electromagnets. In a typical motor, theseelectromagnets are designed so that their poles change just as therotor's north poles have reached the stator's south poles. After thepoles change, the rotor finds itself having to continue turning inorder to bring its north poles closer to the stator's south poles andit continues to experience a twist in the same direction. The rotorcontinues to spin in this fashion, always trying to bring its northpoles close to the south poles of the stator and its south poles closeto the north poles of the stator, but always frustrated by a reversalof the poles just as that goal is in sight.

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