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Epicyclic gear box problem

  1. Sep 19, 2010 #1
    Hi,
    Cant understand this at all, even modelled the set up with lego but still cant fathom it! I cant see how the arm can rotate with locking something.

    Cheers
     

    Attached Files:

  2. jcsd
  3. Sep 19, 2010 #2
    hi, The diagram is a bit misleading. the output shaft is attached to the second sun gear S2. input is S1, the arm just connects the planetary gears (P1 and P2). Just think about it this way. If you have the arm at 0 rpm, you have just a standard reduction between the input and output right? thats easy to work out, lets call that output X. Now, if you have the arm at 300 rpm, matching the speed of the input, the system will be locked, and the output shaft will be at 300 rpm. extrapolate what you find between these two points to find the output at 100rpm.

    Again,
    the output will basically lie 1/3rd between the X (arm = 0 rpm) and 300rpm (arm = 300rpm)
     
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