Simplest possible DC motor+electronics scheme

Discussion in 'OnBoard Electronics & Controls' started by Carioca, Feb 21, 2010.

  1. Carioca
    Joined: Aug 2005
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    Location: BRAZIL

    Carioca Junior Member

    I need to motorise a (standard) lever-operated 1" ball-valve.

    I was thinking of removing the lever and in its place, fitting a nylon gear on the ball-valve shaft, another gear on a dc motor coupled to the former and hey presto......

    Could somebody please offer some guidance on how to go about solving this requirement ?

    Please include off-the-shelf and/or plug-and-play components which may already exist for such applications.

    Many thanks
     
  2. BTPost
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    BTPost Junior Member

    The Question you need to ask yourself is, Do you need Off/On, or Variable Flow? If Off/On the a Solenoid Valve will work, If Variable Flow, then all bets are off....
     
  3. Carioca
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    Carioca Junior Member

    Off/On is exactly what I need, no more, no less !

    Did you say solenoid-actuated ball-valve ?

    Well solenoids are usually associated with linear motion and a ball-valve will require a 90ยบ degree circular rotation (+ and -).

    Say a wiper-motor (auto) shaft coupled to the ball-valve shaft and a pair of limit switches (or motor-drive electronics that would sense the motor stalling at the end of excursion and reduce voltage to zero, if feasible ?)
     
  4. TerryKing
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    TerryKing On The Water SOON

    Carioca, Is this a 1-off personal project, or do you need to make many of these?? There are many motor-controlled valves available.

    If you need to motorize a single already-installed ball valve, that's different..
     
  5. CDK
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    CDK retired engineer

    A wiper motor works well. Mount it near the valve and connect the two with a tie-bar. With the proper geometry you can use the internal switch as a limit in one direction, one NC microswitch for the other one.

    A low power but slower solution is a small toy motor with a threaded spindle and a nut attached to the valve lever.

    Limit switches are the easiest, diehard electronics geeks will use a current sensing circuit.
     
  6. Tim B
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    Tim B Senior Member

    The motor and leadscrew is a perfectly servicable solution, and these are commonly used in home-built milling machines, so there's loads of info on the web.

    The problem with current sensing to determine the end of travel is that usually you'll likely jam it open or closed.

    There are lots of ways to do limit switches. Hall-effect, reed switches and microswitches are just a few that spring to mind.

    Tim B.
     
  7. gonzo
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    gonzo Senior Member

    Tie the solenoid to the end of the handle. If you can't get two way solenoids, use one for each side.
     
  8. BTPost
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    BTPost Junior Member

    My question is, Why are you using a Ball Valve? A simple Bi-Directional Solenoid Driven Valve, would do the same job with a lot less Monkey-Motion. One Solenoid opens the Valve, One Solenoid Closes the Valve. You just Pulse the one that Changes the State of the valve as it is, to what you need, at the time.
     
  9. CDK
    Joined: Aug 2007
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    CDK retired engineer

    As I understood it, the ball valve is in place already and just needs to be motorized, so any discussion about buying an electric valve is beside the point.

    Solenoids are unsuitable. For a 1" ball valve to turn 90 degrees you need solenoids like on a starter motor, drawing 40 amps. You do not want these near you because of the loud bang they make. Even the intake valve of a dishwasher can be disturbing.

    I have 4 electrically operated valves in the central heating system that control the water flow through various heat sources like the solar collector and the open fireplace. They open and close silently at intervals of just a few minutes. My wife would have left me years ago if they would have been solenoid operated!
     
  10. depend if you want some small electronic components withthat in your boat, rest of your problem doesnt sounds to tricky to solve. depends on you want to play with, most of the things for my idea are of the shelf stuff except for some electronic components

    /regards

    p.s. it can be made without electronics if you manually want to do the on off with push buttons
    had to add you can make all very simple and you can also make with lods of additions to your apparatus
     

  11. simplest solution for your problem

    this is my idea of simple solution to your problem, u can also make it very complex to control if want, this one uses two pushbuttons 2-pole a lamp some wire and your motor, the lamp u need to try out manually so the motor runs in its place without the lamp becoming bright just glowing a bit then when motor stops and hits either end the lamp should become bright and u will know it got to one of its endpositions.

    /mike
     

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