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Big rotor vs multiple small rotors in a Permanent Magnet Generator

  1. Oct 23, 2015 #1
    Hello guys,
    I am trying to build a permanent magnet generator, I have 48 magnets and 18 coils, and I am hesitating betwen 2 configurations.
    Configuration A: 2 huge steel plates with 24 magnets on each and an 18 coil stator between them or
    Configuration B: 4 smaller plates stacked to sandwich 3 stators, same total number of magnets and coils.
    In theory, for both configurations, over 1 complete revolution the same number of magnets would pass over the same number of coils. Since voltage is proportional to the variation of flux in time, in config A the speed of the magnets being higher, a higher voltage is obtained, in an open circuit at least.
    But when I add a load current will start flowing and that would slow the rotor. In config A the force will be applied far away from the axis making it easier to slow down the rotor while in config B it will have a smaller impact since it is closer to the axis. Having said all that do you think that I would have the same efficiency for both configurations?
  2. jcsd
  3. Oct 23, 2015 #2


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    For the same power, higher voltage means lower current and lower I^2R losses in the windings.
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