Possible Gear Ratios of Planetary Gear Set

1. Sun gear locked
Ring gear driving
Planet gears driven
Relatively low step-down ratio.





2. Ring gear locked
Sun gear driving
Planet gears driven
Relatively high step-down ratio.





3. Locking two elements together so that the planetary gear set turns as a unit, produces a direct power transmission (1 = 1).





4. Planet gears locked
Sun gear driving
Ring gear driven
Direction reversal and step-down ratio.