Alternator load limit ?

Discussion in 'The Projects Forum' started by janmarsh, Feb 16, 2009.

  1. janmarsh

    Thread Starter Member

    Feb 16, 2009
    12
    0
    Hello all,
    I am building a small permanent magnet alternator from a used AC servo motor.
    The windings are being replaced at the moment.

    When I come to drive the unit for the first time, How will it be possible for me to know when I reach this particular units optimum max. load without gaining any nasty smells ? :)

    Many thanks for any help.
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    Draw a current less than the maximum current the motor is rated.
     
  3. janmarsh

    Thread Starter Member

    Feb 16, 2009
    12
    0
    mik,
    All motor winding has been removed & is being replaced with heavier 1.5mm wire. All coils will be in parallel & the three phases in Delta.

    Should it not be considered a different animal to the original ?

    The output will then be wired to a 150amp rectifier.

    I should have stated this sooner.
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    A 1.5mm wire is able to handle about 3 Amps.

    Coils in parallel are not a good idea because a small phase shift or difference in voltage will cause currents to circulate between them and heat them.

    Also, a delta connection in a generator is not a good idea for the same reason as before. Better to connect them as Wye.
     
  5. janmarsh

    Thread Starter Member

    Feb 16, 2009
    12
    0
    Thanks mik, You have given me serious food for thought. :confused:
     
  6. janmarsh

    Thread Starter Member

    Feb 16, 2009
    12
    0
    I,m out of my depth here.

    I will try & describe the dimensions of my project.

    Permanent magnet rotor has magnets diameter of 50mm, magnet length of 120mm, 6 poles, the drive shaft diameter is 19mm.

    Laminate dimensions are 52mm i.d. 88mm o.d. length 120mm.
    18 segments.

    If you gain sufficient from the proportions I have given here, is it possible for you to give me a rough suggestion of numbers of windings, etc. (1.5mm wire)

    Alternator is to be engine driven.

    I am hoping to gain high amps, low voltage to supply load to hydrogen cells. :)
     
  7. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    I am sorry but I am not a motor designer. I could give approximations but I won't.
     
  8. janmarsh

    Thread Starter Member

    Feb 16, 2009
    12
    0
    I understand. Thankyou for your input. :)
     
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