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How to find shaft torque for belt pulley arragement?

  1. Jul 28, 2015 #1
    I am facing problem in calculating the shaft torque for my system.

    Motor is driving pulley and that pulley is coupled with belt with another big pulley (plz refer attached file image).
    Motor power 19.4 kw, Torque- 71.8 Nm, Motor Rated speed- 2580 rpm, motor shaft dia=42mm
    Pulley dia (refer attached fig):-
    d1=124.78, d2=374.33, d3=124.78, d4=356.51, output shaft speed =291 rpm. (shaft dia is 80 mm)

    How to find the torque of shaft? plz tell me the methodology/procedure ...?

    Attached Files:

  2. jcsd
  3. Aug 2, 2015 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
  4. Aug 2, 2015 #3
    Torque simply multiplies by the ratio of the pulley diameters. The first pulley set diameter ratio is 3:1 so torque multiplies by 3. The second pulley set diameter ratio is 2.86:1 so torque multiplies by 2.86. Overall, torque multiplies by 3 X 2.86 = 8.6. (Note that this ratio is about 3% less than the ratio of overall speed reduction. This is because the effective diameter of a v-belt pulley is slightly less than the outside diameter; in your case, about 4 mm less.)
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