Motor direction control

Discussion in 'General Electronics Chat' started by iONic, Nov 18, 2010.

  1. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007
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    I have a couple of small 60mm 12V fans. I'll call them blowers as they function a bit differently. The intage is from either side of the fan fan blades (parallel to the motor shaft) and the air flow is through a single port that is perpendicular to the fan blades. It works fine in this capacity. However, I was hoping to reverse this operation, pulling the air from the single port and blowing it out of the former intake. Just reverse the source polarity, right? Wrong. It doesn't run!
    But why? Could there be an internal diode or something inhibiting reverse polarity operation? What is your take?

    The fan has only two wires, red and black.

    Thanks

    i
     
    Last edited: Nov 18, 2010
  2. SgtWookie

    Expert

    Jul 17, 2007
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    The fans most likely have brushless DC motors, that are designed to be connected to power only one way. If they don't have an internal protection diode, you probably killed it/them.

    You would not want to run them backwards anyway, as the blade design is optimized for rotating in one direction; You would get extremely poor performance if they were rotated the other way.
     
  3. iONic

    Thread Starter AAC Fanatic!

    Nov 16, 2007
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    It's what I figured, with respect to the blade configuation. They are brushless and must have a diode as I have not killed them yet.

    Thanks SGT.


    i
     
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