Reversing polarity on a small DC motor

Discussion in 'The Projects Forum' started by Vince T, Apr 18, 2010.

  1. Vince T

    Thread Starter New Member

    Mar 12, 2010
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    0
    I am building a 3' model tower crane.
    I want to move the trolley from one end of the jib to the other by reversing the polarity on a small DC drive motor.
    I have looked into using lever actuated DPDT switches at each end of it's path but this will not sustain repeat travel cycles.
    Help is appreciated
     
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
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    Why not use a microswitch at the end of each travel length to reverse the motor.

    SgtWookie has posted a solution to this about 8 times in the past month:

    [​IMG]

    Here is a link to a recent thread that has involved the same info:
    http://forum.allaboutcircuits.com/showthread.php?t=37154

    When you first have a question, try the search options here. A query of reverse motor would have given you may results.

    If you need more specialized info, ask away.
     
  3. Vince T

    Thread Starter New Member

    Mar 12, 2010
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    0
    I like the scheme. I'm a real newbee and must research the component parts. I have found that the IN4004 silicon rectifier requires 1 amp I need to operate this system with 3/9v DC. Can I do it as you said?
    I'm also looking intro the H-bridge circuit as you suggested.
    Much thanks for your help
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    That is the limit of current the diode can pass before it burns up.
     
  5. retched

    AAC Fanatic!

    Dec 5, 2009
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    Depending on how big your "small" motor is, you should be fine.. Should be under the 1A limit before it will let the magic smoke out.

    If you have any specs or manufacture info or preferably a datasheet on the motor you will be using, that will help alot.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    Is the motor in the trolley? Or are you pulling it via chain/cable/string?
     
  7. retched

    AAC Fanatic!

    Dec 5, 2009
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    Carbon nanotubes? ;)

    I was wondering if you have a drawing, plans, or even photo of this contraption.
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
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    [​IMG]
     
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  9. retched

    AAC Fanatic!

    Dec 5, 2009
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    sorry... :)
     
  10. Vince T

    Thread Starter New Member

    Mar 12, 2010
    8
    0
    Thanks guys for all the interest.
    My small motor is 3v dc and is stationary at one end of the jib.
    Sorry it's late can I continue this later?
    Thanks again
     
  11. retched

    AAC Fanatic!

    Dec 5, 2009
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    Sure, see you when you get back. So your not using carbon nanotubes? ;)
     
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