• Demonstration of the function of an epicyclic gear system.
  • To determine and verify the velocity and torque ratios between the input and output shafts.
  • Study of the mechanical advantage and efficiency of a planetary system.
  • Determination of the angular displacement at the input and output and comparison with calculated ratios.
  • Determination of the minimum force at the input to move a weight at the output.

Gears selection:

  • First gear.
  • Second gear.
  • Third gear.
  • Reverse gear.

Power Transmission:

  • Checking the relation between the input motor torque and the output motor torque.



  • Wall mounted unit.
  • Anodized aluminum frame and panels made of painted steel.

Three coupled epicyclic gear sets, formed by:

  • Sun gears.
  • Satellite gears set.
  • Common support of the satellites.
  • External ring.
  • Two graduated discs located at the input and output shafts.
  • Different mechanical pins that simulate the pilot valves used to brake the different planetary components.
  • The shafts of the unit are made in stainless steel. The discs and gears are made in aluminum to facilitate the experiments.
  • The pinions are made of aluminum and are mounted on ball bearings to reduce of losses due to friction, making the practical exercises execution easy.
  • The unit provides three forward speeds and a one reverse speed.
  • In order to carry out some practices with apparatus, two set of weights is provided.
  • The Unit is supplied with instruction manual.

The most important elements of an automatic transmission are one or several planetary gears (or epicyclic gears), clutch packs, band brakes and pilot valves. Epicyclic gears perform several functions:

  • Coupling between input and output shafts.
  • At low velocities, it generates high torque at the output shaft.
  • At high velocities, it reduces the torque at the output shaft.
  • Rotation direction inversion between the input and output shafts.
  • The Epicyclic Gear Unit (3 elements), consists of three coupled epicyclic gears sets. It will allow the students to carry out experiments of different gear ratios, as well as the torque conversions. The epicyclic gears unit are the same and they consist of the following elements:
  • Sun gears
  • Satellite gears set
  • Ring

The unit has two graduated discs located at the input and output shafts, which will allow to check the velocity and torqu ratios according to the application of the different brakes. The power arrives to the epicyclic gears through the sun gears.