How Does a Generator Differ From an Electric Motor?
Electricity and magnetism, though seemingly separate things, are in fact intimately connected. The principle of electromagnetic induction, described by the scientist Michael Faraday in 1831, says that moving electrical charges produce magnetic fields and changing magnetic fields make electrical charges move. Both the electric motor and the electric generator are machines based on this principle. Does this Spark an idea?
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Parts of an Electric Motor
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An electric motor is a fairly simple machine. It contains one or more magnets, which might be either permanent or electromagnetic, usually affixed to the casing of the motor. Between these magnets is an iron armature mounted on an axle around which are wound coils of insulated wire. Attached to the coil is a battery or some other source of electricity.
How an Electric Motor Works
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As the battery is connected to the coil, electricity starts to flow through it. Because magnetic fields cause charged particles to move and electricity is simply the flow of charged particles, the magnets try to make the electrons flowing through the wire move. Because of the way the magnets and coils are lined up this twists the coil around its axis, causing the armature to rotate. In this way, electrical energy is transformed into kinetic energy, the energy of movement.
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Parts of a Generator
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A generator is also composed of coils of wire and magnets. A generator might be assembled much the same way, with magnets attached to the case and an armature wound with coils of wire. It might also be made with the coils of wire affixed to the case and the magnets mounted on an armature on an axle. Either way, the armature is connected to some external motor source. This might be the blades of a wind turbine, a gas-powered motor or even a hand crank.
How a Generator Works
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Whether it is the magnets that are physically moving or the coils that are physically moving does not matter. Either way, they are moving relative to each other. Because of this, the principle of electromagnetic induction causes the magnets to generate an electric current in the coils of wire. This current can be used or stored in a battery.
The Difference
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In essence, an electric motor and a generator are the same thing. They both take advantage of the same natural law. They are just hooked up in reverse, with a motor applying electrical power to the coils in a magnetic field to make them move and a generator applying motive power to the coils in a magnetic field to make them generate electricity. While a generator may be build to have either the coils or the magnets turn, it is easier with motors to only have the coils turn. Other than these minor differences, the two machines are identical.
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- Photo Credit Wind Generator image by Peter Orsaeo Sr from Fotolia.com
