12v go-cart forward/reverse switch.

Discussion in 'General Electronics Chat' started by andysnappy, Feb 3, 2014.

  1. andysnappy

    Thread Starter New Member

    Feb 3, 2014
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    Hi all. Could anyone help me design a circuit to help me fit a reverse switch to my sons converted mobility scooter into a go cart. At the moment it is forward only. A press button opperating a 40 amp relay to send the power to the motor. the max currant draw is 40 amps and 12v dc. I have a 10amp 6 terminal, 3 posision switsh and 2 more 40amp relays to use. Just need to reverse the polarity of the motor with out burning out the 10amp switch. Any help would be greatly appreciated. Thanks.
     
  2. inwo

    Well-Known Member

    Nov 7, 2013
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  3. #12

    Expert

    Nov 30, 2010
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    Here's one, 40 amp relays and a feeble pushbutton.
     
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  4. inwo

    Well-Known Member

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    Here is how I did the grand-kids go-cart with the linked relay.

    It will also work if OP relays have a NC contact.

    The dynamic braking works great. As slow as mine was that's all the brakes I have.
    And it adds some stuck relay protection.

    ps.
    I just notice now while checking for errors.
    A brake switch isn't needed.

    F+ R = Brake
     
  5. andysnappy

    Thread Starter New Member

    Feb 3, 2014
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    Thanks inwo, that's a big help. The circuit shows 2 separate switches for forward and reverse. I would like to use a switch so with the switch in position 1, when the pedal is pressed the car moves forward and in position 2 it goes backward. Any ideas? Thankyou.
     
  6. inwo

    Well-Known Member

    Nov 7, 2013
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    Yup, Just use a toggle switch.
    +12 to foot switch.
    Foot switch to center of toggle.
    One side of toggle to coil F.
    Other of toggle to coil R.

    Selector switch.

    I can redraw if needed.

    I still don't know what configuration your relays are.
    I'm betting bosch type. Little 1" square.

    Hey, I found a picture I've used before.:)
     
  7. inwo

    Well-Known Member

    Nov 7, 2013
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    ps,

    If you are using these.

    Pretty light duty for motor load.

    You absolutely need a master control switch or relay.
    The brake relay I've shown is a start.
    That way when something sticks, there is a way to kill power.
    A fuse or fusable link doesn't hurt either.

    Meaning a short piece of #14 wire somewhere near the battery. Maybe smaller depending on load. If it gets warm when working hard, you're in the ball park.
     
  8. andysnappy

    Thread Starter New Member

    Feb 3, 2014
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    Thank you very much for your help. A redraw of the diagram would be greatly appreciated. They are the same relays I am using.
     
  9. inwo

    Well-Known Member

    Nov 7, 2013
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    Haven't proofed this yet. Have to run.
    I'll see if someone checks it before I get back.

    No safety circuits shown.
    This circuit will brake when throttle is released.

    I'll add my brake circuit when I get a chance.
     
  10. #12

    Expert

    Nov 30, 2010
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    Kudos. Less number of relay contacts in series compared to my drawing.
    I bow to a superior design.
     
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  11. inwo

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    Thanks, but I cheated.
    I actually built this a couple years ago.

    I'm not done yet.:(
    I'm sure OP won't be happy with the brake.

    Yours free wheels at least.:)

    Now by the time I add another relay..................who knows.
     
  12. inwo

    Well-Known Member

    Nov 7, 2013
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    Can you pick up a couple general purpose 1A diodes?
    A few extra will improve switch life.

    You will like this better.

    With this set up, cart will coast to a stop unless you pull in RY3 from an added switch.

    That's what I did on mine. Another momentary foot switch.

    Of course, your motor may have a free-wheel clutch and make this moot.
     
    Last edited: Feb 3, 2014
  13. #12

    Expert

    Nov 30, 2010
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    No. Anytime a DC motor has its power wires connected together, it brakes.
     
  14. inwo

    Well-Known Member

    Nov 7, 2013
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    I'll look again. Thought yours did not.:confused:

    edit:

    Look again. Thought that's why you added a relay.
    Which by the way, mine needs too.
     
  15. BillB3857

    Senior Member

    Feb 28, 2009
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