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Thread: Alternating Generators

  1. #1 Alternating Generators 
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    Can someone please explain why Generators produce A.C current?


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  3. #2  
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    It's the law of induction. The EM voltage induced in a closed loop is equal to the opposite of the variation of the magnetic flux through that surface. Basically, if a loop is moving in a variable magnetic field, a variable tension is induced in the loop.

    AC generators work by this law -- except that rather than making the magnetic field variable (which is not always easy), they keep a fixed magnetic field (either with permanent magnets or with electromagnets) and rotate several loops (windings on the rotor) in that field. The windings see this as if they were moving through a variable magnetic field and electrical tension is induced. See if this helps.


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  4. #3  
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    It's the law of induction. The EM voltage induced in a closed loop is equal to the opposite of the variation of the magnetic flux through that surface. Basically, if a loop is moving in a variable magnetic field, a variable tension is induced in the loop.

    AC generators work by this law -- except that rather than making the magnetic field variable (which is not always easy), they keep a fixed magnetic field (either with permanent magnets or with electromagnets) and rotate several loops (windings on the rotor) in that field. The windings see this as if they were moving through a variable magnetic field and electrical tension is induced. See if this helps



    I did not really understand that answer - could someone simplify it - to a iGCSE level

    thanks
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  5. #4  
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    Are you asking why a-c is used instead of d-c, or are you asking how an a-c generator works?

    A-c has the advantage of being easily transformed (with a transformer) to different voltage levels so that it can be efficiently transmitted, and changed to a safer voltage at the point of use.

    An a-c generator basically works by spinning a magnet inside a coil of wire. As the magnetic field changes first in one direction, then in another, it induces a voltage in the coil of wire first in one direction, then another.
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  6. #5  
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    I'll try to make it simpler: the point is, if you have loop of wire in a magnetic field that is not constant, a voltage is induced in the wire.

    AC generators have a lot of wires that are rotated in a fixed magnetic field. The wires "feel" this as if the field was variable, and so a voltage is induced in them.

    I don't think I can get it much simpler than that .
    grep me no patterns and I'll give you no lines
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