A planetary gearbox refers to a gear system where one or more ‘world’ gears rotate around a central ‘sun’ gear. Typically, a planet carrier is driven by the input torque which rotates the planets around a set outer ring (sometimes referred to as the annulus). Therefore drives sunlight gear which then supplies the output torque. However there are types of the additional combinations, such as the sun gear being set and the band providing output torque.
The main benefit of planetary gearboxes are their high power transmission efficiencies. Typicially this can be around just 3% per stage. Further to this, the high effiency is certainly delivered despite the compact style giving a large torque to size/weight ratio. A few of this is thanks to the load sharing occurring across the multiple planet gears.
A planetary gearbox refers to a gear system in which one or more ‘planet’ gears rotate around a central ‘sun’ equipment. Typically, a world carrier is driven by the input torque which rotates the planets around a fixed outer ring (sometimes known as the annulus). Therefore drives sunlight gear which then provides the output torque. However there are examples of the other combinations, like the sun gear being set and the band providing output torque.
The main advantage of planetary gearboxes are their high power transmission efficiencies. Typicially this is often around just 3% 
per stage. Further to this, the high effiency can be delivered regardless of the compact style giving a huge torque to size/weight ratio. Some of this is thanks to the load sharing that occurs over the multiple planet gears.
Reliable Small Planetary Gearbox
EP Motor’s small planetary gearbox is available in 7 different sizes with diameters of 16mm, 22mm, 26mm, 28mm, 32mm, 36mm, and 45mm, each consisting with mono and multi-stages, and the apparatus ratios range between 3.3:1 ~ 1500:1.