Does a planetary gear system affect the torque felt by an electric motor?

[ENgez]

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, because i read that the planetary gears increase transmitted torque (the engine will "feel" less torque) as result of decreasing rotation speed

 

[huntoon]

What engine are you referring to?

 

[ENgez]

a simple dc engine that supplies torque using a shaft .it has no built in gearbox.

 

[huntoon]

I thi

 

[huntoon]

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.

 

[Pkruse]

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.