Planetary gear sets are smaller and more compact, and this limits heat dissipation. To keep the gears cool, the lubricant can be sent through a heat exchanger, or a cooling fan can be designed in.

Early automatic transmissions with names like Hydra-Matic, Dynaflow, ZF, and Hondamatic delivered simplistic driving, but heavy planetary gear systems and torque converters sacrificed fuel efficiency.

Actually, this is not the first laser-cut planetary gear clock that we have seen. In case you are wondering about the advantages of planetary gearboxes, you might want to check out how a 3D ...