Make a motor spin in two diffrent ways?

Discussion in 'General Electronics Chat' started by Robin Mitchell, Apr 21, 2010.

  1. Robin Mitchell

    Thread Starter Well-Known Member

    Oct 25, 2009
    Hi everyone,

    How can you make a motor spin one way, and then when a signal is sent to the circuit, it spins the other way by reversing the polarity. I cant seem to think of a way of doing this.

  2. retched

    AAC Fanatic!

    Dec 5, 2009
    SgtWookie has posted this circuit a few times, It may be what your looking for.


    If you wanted to reverse the motor when a limit was hit, this will do it.

    If not, you can see how the spdt relays are used to swap poles.
  3. SgtWookie


    Jul 17, 2007
    The circuit I drew that Retched posted requires manual input (pushing a switch and holding it).

    You really need to define your requirements better than what you have already.

    Generally, it is very hard on a DC motor when it's running full speed in one direction, and you suddenly reverse the voltage polarity across its' terminals. You can quickly burn the motor out if you do that.

    Ideally, you run the motor in one direction, and then either brake it to a stop by grounding/shorting both terminals, or allowing it to coast to a stop - and then applying voltage in the opposite polarity.

    Relays are cheap, but slow. If you want better response, and the ability to do things like PWM, you will need a semiconductor H-bridge.
  4. Robin Mitchell

    Thread Starter Well-Known Member

    Oct 25, 2009
    Is it possible to use transistors instead of relays?

    Also, i have a turret which turns left and right, when it touches a contact plate on either side it reverses direction. Because its only touches the plate a 4013 can be used to remember the input.
  5. daviddeakin

    Active Member

    Aug 6, 2009