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Jib crane moving with the wind

  1. Apr 9, 2012 #1
    Across the street from my apartment there is a building under construction and a large jib crane is right outside my window. Today we have 20-30mph winds. All construction workers have gone home for the day. I see that the crane is rotating back and forth. It's very unnerving, but as I read perfectly normal and necessary. I just wonder how it knows where to point and what is controlling it. For a few minutes it was rotating quite a bit back and forth. However now it looks to have stopped yet the winds are still blowing quite hard. Is it just moving with the wind or is there some sort of motor and computer system to tell it where to point? What happens if a severe storm hits? Can the crane survive 60-70-80mph gusts?
    Last edited: Apr 9, 2012
  2. jcsd
  3. Apr 9, 2012 #2


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    Staff: Mentor

  4. Apr 10, 2012 #3


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    This one seems to go into windmill mode:


    The motors work as generators and charge the batteries!
  5. Apr 11, 2012 #4
    Standard procedure is to let them weather vane. The the other option is to let them collapse due to side loading. They will tolerate a great deal of wind this way.
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