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Discussion in 'The Projects Forum' started by seayaker, Jan 29, 2009.

  1. seayaker

    Thread Starter New Member

    Jan 27, 2009
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    If a simple 2 pole permanent magnet generator were to be commutated without brushes, and operates between 10-50v (before regulation) and between 5-30 amps what kind of scrs or triacs should be used?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    This is hard to understand -
    The brushes make the sliding electrical contact to the armature. The commutator is segmented to switch the DC field polarity induced in the armature to produce the properly polarized magnetic field that spins the motor.

    Can you explain what you are trying to do a bit further?
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Our OP is talking about generators, not motors.

    Actually, you don't really need SCRs or TRIACs, you could use some bridge rectifiers. How many you'll need depends upon how many coils your generator has.
    Have a look at this .pdf document:
    http://www.scoraigwind.com/pmgbooklet/itpmg.pdf
    Rectification and star/delta topologies are discussed on pages 38 through 44 or so.

    Synchronous rectification using MOSFETs and driver circuits would be more efficient than standard rectifiers, but a good bit more complex.
     
  4. seayaker

    Thread Starter New Member

    Jan 27, 2009
    4
    0
    I tried full wave bridge rectifiers in every possible way. I was still loosing half my output. I realized what was happening is that the current was flowing against the pole that was being energized in opposite polarity. if you draw the circuit you can see this. I thought I could do it with diodes but a full wave bridge won't work. The poles have to be switched so that current can flow in the right direction in both poles. I used a 2 pole generator for simplicity there are actually 32 coils but it's the same principle. the same as if you took an old generator and removed the mechanical commutator and set out to switch the poles electronically. if any one has any experience with this please respond.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Did you read through the PDF file that I linked to?
    It shows a few different ways to connect the coils; star and delta.
     
  6. seayaker

    Thread Starter New Member

    Jan 27, 2009
    4
    0
    Yes I did and thanks, however mine is single phase and the poles have to be reversed I can't just reverse current flow. How does it perform? How many watts at say 25 mph. wind?
     
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