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Thread: Gear torque --- help me please

  1. #1
    Associate Engineer
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    Gear torque --- help me please

    I am trying to make a lift for my sister's farm. Please help with this problem....thank you.

    20 inch diameter geared cable spool is driven by a 2 inch spur gear. The load is 1500 pounds.

    How many ft/lbs torque is require at the 2" gear to lift the load at 30 feet per minute?

    Thanks in advance for your time and help.
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  2. #2
    Technical Fellow Kelly_Bramble's Avatar
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    r1 x F1 = r2 x F2

    or

    (r1 x F1)/r2 = F2

    Where:

    r1 = radius large gear
    r2 - radius small gear
    F1 = force applied small gear
    F2 = force applied large gear

    torque= r x F

    torque large gear = F2 x r2
    Last edited by Kelly_Bramble; 11-08-2015 at 09:22 AM.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

  3. #3
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    Thanks Kelly, but I am confused

    F1 value is unknown. What I am trying to do is find how much motor torque is needed (2 inch pinion) to lift 1500 pounds connected to a 20 inch diameter cable drum.

    I am I looking at this wrong? Sorry I'm not a ME.

    Thank you kindly for you response




    Quote Originally Posted by Kelly Bramble View Post
    r1 x F1 = r2 x F2

    or

    (r1 x F1)/r2 = F2

    Where:

    r1 = radius large gear
    r2 - radius small gear
    F1 = force applied small gear
    F2 = force applied large gear

    torque= r x F

    torque large gear = F2 x r2

  4. #4
    Technical Fellow Kelly_Bramble's Avatar
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    ?

    torque small gear = F1 x r1

    Instructional Video:

    Gear to Gear Torque Calculations
    Last edited by Kelly_Bramble; 11-08-2015 at 11:17 AM.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

  5. #5
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    Thanks Kelly.

  6. #6
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    Is this answer correct

    Quote Originally Posted by Kelly Bramble View Post
    ?

    torque small gear = F1 x r1

    Instructional Video:

    Gear to Gear Torque Calculations
    The driven gear is 20" dia. The driving gear is 2" dia.
    The ratio is 10:1
    To lift a 1500 lb load on the 20" dia gear, 150 in/lb torque will be required.

    Correct??????????

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