Reverse rotation twice a second

Discussion in 'Homework Help' started by Danny Vain-Nielsen, Oct 26, 2015.

  1. Danny Vain-Nielsen

    Thread Starter New Member

    Oct 26, 2015
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    Hi all!

    I'm a an engineering student, and I don't know a whole lot about DC motors. Is it possible for a DC motor to reverse rotation twice a second? We need that kind of movement for a shaft. We might also have to make the rotational angle adjustable, meaning sometimes 180 degrees, other times 150 degrees. Is that possible and easy for a newbie to program?
     
  2. MaxHeadRoom

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    Jul 18, 2013
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    Depends on the inertia of the armature and the load.
    Do you intend accurate positioning?
    If so you either need PID feedback or use a stepper motor.
    Max.
     
  3. Danny Vain-Nielsen

    Thread Starter New Member

    Oct 26, 2015
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    The torque is quiet heavy. 57 NM. Do you know an easy and inexpensive way to doing this?
     
  4. joeyd999

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    Jun 6, 2011
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    A linear actuator?
     
  5. MaxHeadRoom

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    Jul 18, 2013
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    57N-m, That is a considerable load, I envision some kind of gearing to use an small motor.
    Is it possible to use a linear actuator to operate a small rack with a pinion on the shaft.
    You may want to employ one of the free sizing programs to get an idea of sizing.
    Such as Kollmorgen graphical motor sizing.
    Max.
     
  6. joeyd999

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    Why rack and pinion? Sounds like he just wants to move a shaft. Direct drive from the actuator.
     
  7. Danny Vain-Nielsen

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    Oct 26, 2015
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    I asked a big company doing linear actuators and they had none, that could move so fast.
     
  8. MaxHeadRoom

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    Smaller linear actuator with extra gearing, there has to be some kind of linear to rotary connection anyway.
    Max.
     
  9. MaxHeadRoom

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    How did they assume you were transferring to rotary?
    Max.
     
  10. crutschow

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    Mar 14, 2008
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    Here are some high torque stepper motors (up to 50 Nm), but I don't know their cost.
    You could likely use one of those with a gear reduction to increase the torque.
     
  11. mcgyvr

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    Oct 15, 2009
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    What about a mechanical solution like a crank so you never need to change direction but get the same motion effect..
     
    JohnInTX and shortbus like this.
  12. Biff383

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    Jun 6, 2012
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    30hz for any motor seems to be asking a lot. Maybe better to think about a solinoid? Way simple in the US. Not all that difficult in the rest of the world.
     
  13. kubeek

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  14. crutschow

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    Where did you get 30Hz? :confused:
    The OP wants twice a second or 2Hz.
     
  15. kubeek

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    Probably mistaken for 30 RPM.
     
  16. Biff383

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    Jun 6, 2012
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    Yup.
     
  17. Biff383

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    Jun 6, 2012
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    Oops.
     
  18. MaxHeadRoom

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    I have a large NEW unused Bayside precision planetary through-hole gear box 15:1 with 180Nm output.
    The original cost was around $2000 yours for $150.00 + shipping.
    Max.
     
    Last edited: Oct 27, 2015
  19. Danny Vain-Nielsen

    Thread Starter New Member

    Oct 26, 2015
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    We will look at it... our budget is around 6500 € for everything the machine needs. But the school want us to buy only from wellknown companies.

    I think the solution is to choose a 400 W DC motor and install to a constant speed at 60 rpm and then making a crank to get the forward and backwards movement.
     
  20. MaxHeadRoom

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    I assume you are in Europe, so the shipping could be high.
    But this is it, it was purchased for a project and never used, I am now semi-retired so it is suplus now.
    Max.
     
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