Planetary Gearboxes consists of three major components:
  • Sun gear
  • Planet gear
  • Ring gear

The sun gear is meshed around with the planet gears, which in turn are meshed with ring gear. Planet gears are connected to each other by a carrier, which helps them to rotate around the sun gear.

Advantages of Planetary system over helical gearbox:
  • They are compact and take less space and are light weight, as the load is shared between the planet gears.
  • The noise and vibration is reduced as the load is shared. This also increases efficiency.
  • Since the shafts are inline and concentric, bending moment is absent.
  • The manufacturing of these components is relatively cheaper due to smaller size as compared to parallel axis gearboxes.
Disadvantages:
  • The gear system is complex and needs precision manufacturing.
  • Teeth ratios are specific and assemble is according to them.
  • Calculations of efficiency are a bit difficult.