# Epicyclic gearset with two suns and two planets

I'm developing an hybrid boat motor for an university project. Searching on the internet for some gearset under the instruction of my professor to not use internally toothed gear wheels, I found this one:

In the same website (http://www.benchtophybrid.com/PG_Types.html), there are two animations, one keeping the orange sun fixed while rotating counterclockwise the green one, and the other keeping the green one fixed, while rotating counterclockwise the orange one. In the first one the animation shows that the carrier rotates clockwise, but in the second one the carrier rotates counterclockwise.

My question is: shouldn't the carrier rotate clockwise in both cases?

And another doubt concerning this epicyclic gear: is it correct saying that the ratio formula is: e=(w1-wp)/(w3-wp) even if the sun gears are connected to the motors (electric and thermal)?

• you are reversing the rotation of the green gear relative to orange gear ... in the second scenario, the orange gear would have to be spun clockwise to keep the relation between the gears the same Commented Jul 30, 2023 at 17:04
• Sorry, can you clarify your answer? The 2 cases I'm talking about are descripted from the same point of view, which is from the side of the green one (so watching also the carrier) Commented Jul 31, 2023 at 10:05
• Try deriving a general equation for the gears, relating: rotation of green, rotation of orange, rotation of the gray part about green shaft, rotation of yellow about gray shaft. Equation mist hold true regardless of what gear you hold stationary.
– Abel
Commented Jul 31, 2023 at 13:00