1. jack mcleod

    Thread Starter Member

    Sep 4, 2007
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    Wish to spool 5/8" rope onto a revolving drum. The drum is approx. 2' long,with a 12" diam and the axle is 2" diam. The spooling mechanism (similar to a fishing reel) goes back and forth through a moving eye mounted on a nut on a threaded rod. The rod is driven by a DC (reversible) 12 V motor. As the rope layers build on the drum the eye needs to move faster as the drum speed is constant. Micro controllers are beyond my scope. How may one control the motor speed turning the threaded rod to accomplish an even spooling automatically?
     
  2. John P

    AAC Fanatic!

    Oct 14, 2008
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    It's true that the more rope you have on the drum, the faster it will be pulled in. But wouldn't the time taken to add one more layer be constant, because although there is more rope coming in, it's spread over a larger circumference? I'm thinking that the mechanism that distributes the rope on the drum actually should run at constant speed relative to drum rotation.
     
  3. MrChips

    Moderator

    Oct 2, 2009
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    The eye moves at constant speed relative to drum rotation. For every revolution of the drum, the eye moves one rope diameter.
     
    ErnieM likes this.
  4. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    It goes like that in every crane / derrick system I seen ever.

    Maybe, it could be that the whole thing (drum + eye) goes faster or slower but, one with respect to the other, they should maintain the ratio.
     
  5. jack mcleod

    Thread Starter Member

    Sep 4, 2007
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    Thanks, gentlemen. You! Saved me some unneeded work and improved my knowledge of physics. The happy biologist, Jack
     
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