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Belt pull on v-belt mower deck

  1. Feb 12, 2013 #1

    I'm trying to find the belt pull on a mower deck. The deck consist of 3 spindles and a spring loaded back idler with one v-belt.

    The engine driving the spindles is a 20 HP twin cylinder engine operating at 3600RPM. Main drive spindle is 3600 rpm (1:1 ratio) Engine manual says max torque is 32.5 ft lbs @2500 rpm.

    What I did was use a small hanging scale fixed to the deck with the other end of the scale fixed to the belt.

    I then used a torque wrench on the main drive spindle until either the belt slipped or until I reached 33 ft-lbs. Which ever came first. I reached the 33 ft-lbs before the belt slipped. The scale showed there was 165 lbf on the belt.

    Would this be a correct method to determine belt pull? Would RPM's, weight of the spindle, mower blades need to be considered? If so how?

    Reason I'm trying to find the belt pull; so I can design the spindle shaft and find the bearing loads to size bearings.

    I did use gates design IQ for this. It was great but says I need more than one belt and I think the tension it says the belts should have is much greater than is actually there.

    Thank you for the help!
  2. jcsd
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