Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Torque estimate ?

  1. Feb 16, 2008 #1
    Guys, I have a solar panel screwed onto a shaft which connects directly to a servo motor shaft. How much should the torque rating of the servo be to be able to rotate it ? I mean an estimate of the minimum torque required. The panel weighs 0.8kg plus a few grams for the solar panel holder (made of perspex). No gears are used.

    Thank you.
  2. jcsd
  3. Feb 16, 2008 #2


    User Avatar
    Science Advisor

    You'll need an estimate of either the radius of gyration or the moment of inertia about the rotating axis. You will also have to either assume or specify a rate of angular acceleration about that axis.
  4. Feb 17, 2008 #3
    I would need the servo shaft to rotate a total of 135 degrees, rotating a few degrees every half an hour for eight hours (It will operate like a stepper, stepping during each hour). The speed of rotation is not important, as long as it rotates. The panel's length is 32cm and height is 18 cm. It is a sun tracker.

    There will also be another servo to rotate the round base.

    Pls see diagram attached below.

    Does this help ?

    Attached Files:

  5. Feb 17, 2008 #4


    User Avatar

    Staff: Mentor

    If the collector is balanced, and with the angular velocity being small, the torque required from the motor is tiny. I'd look into a telescope clock drive (if they still make them). Otherwise, you can get a stepper-motor upgrade kit, but they are more expensive than one that just plugs in and runs at the clock rate.
  6. Feb 17, 2008 #5
    How tiny ? The panel weighs 0.8kg. Is this servo sufficient (3.40 kg-cm torque) ?


    What about the servo at the bottom (there will be some bearings below the base) ? It seems like the top would be a bit heavy. The whole frame will be made of perspex.
    Last edited: Feb 17, 2008
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Torque estimate ?
  1. Frf estimation (Replies: 3)

  2. Heat Transfer Estimation (Replies: 15)