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Reversing circuit help

Discussion in 'General Electronics Discussion' started by ktmtragic, Nov 14, 2012.

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  1. ktmtragic


    Nov 14, 2012
    I would like to build a reversing circuit to control a motor using 2 relays. All I need is relay 1 energizes for 20 seconds then deenegizes a five second delay and then relay 2 energizes for 20 seconds and deenergizes and this sequence continues repeatedly. The rest of the controls on the machines are 240V AC.
    I would like to make this board as simple and robust as possible. The last time I built a circuit board was 20 years ago for my electrical trade test so guys please keep it simple and thanks in advance:)
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    Jan 21, 2010
    I would recommend you have an oscillator that operates at 0.2 Hz (one cycle every 5 seconds).

    This drives a 4017 where you connect (via diodes) the first 4 outputs to a transistor which activated relay 1. you skip the next output and similarly connect the next 4 outputs to relay 2.

    That will give you 20 seconds relay 1, 5 sec delay, 20 sec relay 2, 5 sec delay, ... repeated ad infinitum.

    It's not entirely trivial, but it's not too hard either.

    Given that it used CMOS, I'd use a 40106 hex schmitt trigger to make the oscillator.

    How important is the timing? is +/- 10% acceptable?
  3. ktmtragic


    Nov 14, 2012
    Thanks Steve for your response.
    Timing accuracy is not an issue. Is it possible for you to do a drawing/ sketch?
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