Why aren't magnet generators more mainstream?

Discussion in 'General Science & Technology' started by garbonzo, Sep 14, 2014.

  1. Motor Daddy Valued Senior Member

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  3. leopold Valued Senior Member

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  5. billvon Valued Senior Member

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    Alternators are generators.
     
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  7. leopold Valued Senior Member

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  8. Motor Daddy Valued Senior Member

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    You're welcome. You got it from there?
     
  9. leopold Valued Senior Member

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    and you are what again?
     
  10. exchemist Valued Senior Member

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    The opening para from the Wiki article on "Alternator":-

    " An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature [1] but occasionally, a rotating armature is used with a stationary magnetic field; or a linear alternator is used."
     
  11. leopold Valued Senior Member

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    alternators and generators are two different things.
    one (alternator) produces AC, the other produces DC.
    the operation is the same but the construction is different.
    one cannot usually replace the the other unless additional circuitry is used.
     
  12. origin Heading towards oblivion Valued Senior Member

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    Do you just make this stuff up as you go along. Look up AC generators on google. This is really pitiful.
     
  13. leopold Valued Senior Member

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    i don't need to look up anything, i know EXACTLY what i'm talking about homer.

    edit:
    i will keep with your "terminology" though.
    we shall refer to one (alternator) as a AC generator, and the other as a DC generator.

    in your own words origin, do you know the difference, and can you provide links to a DC generator with a rotating magnetic field?
     
  14. Motor Daddy Valued Senior Member

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    That's what it says. Do you agree?
     
  15. billvon Valued Senior Member

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    No, they are not. Every generation plant in the US, for example, uses alternators for their generators.
    Sure, right here: http://www.rockyhydro.com/Generators.php
     
  16. Motor Daddy Valued Senior Member

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    leopold,

    I think I can clear up your confusion. The "Alternator" that you might be thinking of is actually a rectified generator. It is a generator that has a rectifier to convert the AC that a generator normally produces, to the DC requirement of the vehicle electrical system.
     
  17. leopold Valued Senior Member

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    when does a AC alternator use a commutator, and why does a DC generator need one?
    AC generators use slip rings, not commutators, that's why AC generators need rectifiers to produce DC.
    yes, they are two different items bill.
    not a very good description, and no schematic.
     
  18. origin Heading towards oblivion Valued Senior Member

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    Move the bar much?

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    Why do some people have so much trouble admitting they made an error?
     
  19. billvon Valued Senior Member

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    Many AC generators use no slip rings OR commutators. Same with DC generators - and many of those don't use rectifiers.
    All the above are generators. The details on their construction, commutation and operation vary greatly.
    You asked for an example; I provided one. If you would like further information let me know.
     
  20. leopold Valued Senior Member

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    some use no moving parts at all.
    you know exactly what i am talking about bill.
    DC generators use a commutator, and i've yet to see such a machine with a rotating magnetic field.
    where are they?
    provide a schematic this time.
     
  21. billvon Valued Senior Member

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    Exactly!
    DC generators use a commutator, or rectifiers, or a three phase drive, or a vector drive. You could certainly make a permanent magnet rotor generator with a commutator, although there is really no practical advantage over rectifiers, which is why it's not generally done.
    In my electric bike and my Leaf, as two examples.
    See below.

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  22. leopold Valued Senior Member

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    this, my friend is a 3 phase inverter.

    listen, i'm not going to argue the point anymore.
    a generator uses a PM or EM field and the output is taken from the rotor from commutation.
    an alternator uses a rotating field and the output is taken from the stator and must be rectified.
    2 different machines, totally.
    case closed, i'm done.
     
  23. billvon Valued Senior Member

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    Correct. It is used to replace commutators and/or diodes.
    In the future you should make it clear that you are using different definitions for words than everyone else does; it would save a lot of time.
     

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