This apparatus is designed to demonstrate the concept of epicyclic gear train and its application in machines. Epicyclic gears is the combination of gears in which center of one gear rotates about the center of another gear.
In this apparatus there are two epicyclic gears coupled together. Epicyclic gears contain sun gear at center and three planet gears meshed with sun gear and outer ring gear meshed internally with the planet gears. Lock pins are used in the whole mechanism to provide different speed ratio or gear ratio and mechanical advantage. In this way students can perform different experiments in this apparatus and calculate gears efficiency at different gear ratio and torque ratio.