Putting together big crane - Page 2
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  1. #21
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    Quote Originally Posted by true temper View Post



    Sent from my iPad using Tapatalk
    East of Champaign,il I watched them mount one blade at a time, not all three blades at once, blades there were 75 feet long. Generators were 3 megawatts. Each mill on its own 16 acres. Takes a year to do a wind study of the potential Farm., before they say yea or neah. A farm can even take 50 some owners of land to complete a single farm

  2. #22
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    Quote Originally Posted by machtool View Post
    As is mentioned latter in the thread, they have 4 slew motors. More often than not, they are a slave / master arrangement. The ring gear isn't uber accurate. They run two primary rotation motors, then bias the other two motors at lower torque, against the drive to take up the back-lash. You have to consider all this stuff sits a top of a weldment. No reason to induce ground tolerance gearing.

    Regards Phil.
    Yeah it sits on a weldment, but that weldments been on a large HBM or similar and had the mounting face machined off nice and flat + the very generous qty of bolt holes plopped in, certainly most the better large excavators i have personals worked on had hardened and ground gearing, that said, a excavator will probably do more cycles of slewing back and forwards in a day than most cranes will in there life time.

    Slew-rings often get made from forgings, normally VTL then for turning then heat treat then back on a vtl setup with a grinding head for the race ways. Larger sizes, if they wear to the point of sloppy and the gearing is not too bad you can generally send em back in for re-manufacture, were they will simply grind the roller way out for the next size up rollers. I believe they also offered regrinding the gear teeth back and then cutting a non stock pinion for the slew motors. Larger slew rings don't run balls either they run crossed rollers for the load carrying capabilities.

  3. #23
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    Larger slew rings don't run balls either they run crossed rollers for the load carrying capabilities.[/QUOTE]

    Can you explain crossed rollers?

  4. #24
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    https://www.practicalmachinist.com/v...-grinder-1.jpg

    Here is a picture of crossed rollers taken from a surface grinder story in the rebuilding forum.


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