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Automotive How do I calculate required torque for two dc motors?

  1. May 7, 2016 #1
    I am doing a design project but i'm kinda stuck with choosing motors because i am not sure of the required torque. My project is a handicapped golf vehicle powered by 2 motors, so it would need to be able of climbing steep gradients.
    I currently have an equation but I am not entirely sure if it's right.
    It consist of :
    1. Rolling resistance = (Gross Vehicle Mass) X (Co-efficient of Rolling Resistance)
    2. Grade resistance = (Gross Vehicle Mass) X ( Sin(angle of max gradient) )
    3. Acceleration force = (Gross Vehicle Mass/Gravity) X Acceleration
    Adding all 3 up to give you Total Tractive Effort.

    That's then used in the equation
    Torque = (Friction factor for bearings and axles, etc.) X (Total Tractive Effort) X (Radius of drive wheel)

    My question is, are these equations right or do I need to use more complicated equations dealing with moment of inertia, etc.

    Thank you!
  2. jcsd
  3. May 7, 2016 #2

    jack action

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    These are the right equations to use.

    To take into account the rotational inertia, you only need to add a mass factor to the third equation. More info on this page.
  4. May 11, 2016 #3


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    I think that should be..
    Acceleration force = Gross Vehicle Mass X Acceleration
  5. May 18, 2016 #4
    Sorry for the late reply; but thank you.
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