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help reversing dc motor polarity using reed switches and relays?

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by mark2010, May 28, 2010.

  1. mark2010

    mark2010 New Member

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    I have a 12vdc motor which runs at 6rpm. I have an object that I want to travel from left to right and back again using a rack and pinion gear system. The idea is that when the object hits one end, it hits a reed switch which reverses the motor polarity and sends it back over and over again.

    The problem is that I am new to hooking such devices up and dont, know what I need. Do I need two relays to hook this up or just one and how many pins would the relays need to have?

    I would appreciate any feedback!!
     
  2. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi Mark.
    This is one option, uses 2 pole c/o relays and micro-switches.
     

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    Last edited: May 28, 2010
  3. colin55

    colin55 Well-Known Member

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    AUTOMATIC FORWARD-REVERSE
    The following circuit allows a motor (such as a train) to travel in the forward direction until it hits the
    "up limit" switch. This sends a pulse to the latching relay to reverse the motor (and ends the short pulse). The train travels to the "down limit" switch and reverses.
    [​IMG]

    If the motor can be used to click a switch or move a slide switch, the following circuit can be used:
    [​IMG]



     
    Last edited: May 28, 2010
  4. dave

    Dave New Member

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  5. MRCecil

    MRCecil Member

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    I have another solution that employs a minimum number of parts for the continuous shuttle motion you describe. It will take two micro switches, one normally open and another normally closed and a three pole double throw relay with a 12V coil. The schematic is attached with notes outlining the operation. I forgot to add a 1N4001 across the relay coil (anode to same terminal as SW1).

    Good Luck!
     

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  6. colin55

    colin55 Well-Known Member

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    If you cannot get a triple-pole change-over relay, use this circuit:
    [​IMG]
     

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