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Motor and planetary gears

  1. Jul 29, 2012 #1
    lets say i have an electric dc motor and i connected its shaft to a planetary gear system. this planetary gear systems last stage's ring (outer rim) spins a drum. this drum feels an outer torque T as a consequence of loads. my question is motor will feel torque T, becuase i read that the planetary gears increase transmitted torque (the engine will "feel" less torque) as result of decreasing rotation speed
  2. jcsd
  3. Jul 30, 2012 #2
    What engine are you referring to?
  4. Jul 30, 2012 #3
    a simple dc engine that supplies torque using a shaft .it has no built in gearbox.
  5. Jul 30, 2012 #4
    I thi
  6. Jul 30, 2012 #5
    I think your motor will indeed "Feel" this torque T from load. It will be divide by the diameter of the drum, then divided by the gear ratio to get the final torque on the motor.

    I do believe that if the motor and gearing are appropriate this drum load torque will be "seen" by the motor as work to do, nothing special. For example, if this were a car, it would be similar to drag or going up a hill.

  7. Jul 31, 2012 #6
    Motor and load will not see the same torque. They will be different by a factor equal to the gear ratio. If you are trying to balance the sum of the moments in a free body diagram, then don't forget that the difference on torque is taken out by the gear box case.
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