Epicyclic gears get their name from their earliest program, which was the modelling of the motions of the planets in the heavens. 
Believing the planets, as everything in the heavens, to be perfect, they could just travel in ideal circles, but their motions as viewed from Earth cannot end up being reconciled with circular movement. At around 500 BC, the Greeks invented the idea of epicycles, of circles traveling on the circular orbits. With this theory Claudius Ptolemy in the Almagest in 148 AD was able to predict planetary orbital paths. The Antikythera Mechanism, circa 80 BC, got gearing which was able to approximate the moon’s elliptical route through the heavens, and also to correct for the nine-yr precession of that path.[3] (The Greeks could have seen it not as elliptical, but instead as epicyclic motion.)
EP, a versatile and multi-use answer, is not merely another simple planetary gearbox. EP high-tech planetary reducer is usually a true integrated concept, including different functions combined alongside one another to give you a complete Planetary Reducer Gearbox sub-assembly to the most demanding machines.
EP is the ultimate high-tech servo-reducer, specially dedicated to designs requiring:
Superior output torsional stiffness
Ultra-high output radial stiffness and Tilting moment
Patented output bearing design
A high-tech planetary gear train, predicated on REDEX’s differential know-how
ISO 9409-1 productivity drive flange for installation pinions, pulleys, couplings, etc.
High input speeds
Superior acceleration and good torque density
Minimum backlash (1 – 3 arc-minutes)
In-Line or right angle arrangements
This versatile design helps it be easy for design engineers to find exact solutions to the most demanding applications.
Parallel shaft Gearmotors
Helical Single-Stage
The S Series design produces this gearmotor particularly effective for pump, fan and blower applications. To meet up the needs of clients in these sectors, the S Series is also available in the foot or flange types and can be completed with a wide range of electric motors entirely produced by EP. Asynchronous motors both IEC and small (B-BE-BX/M-ME-MX), servomotors (BMD) and reluctance motors (BSR) can be coupled with the S Series: with the breadth of its portfolio, EP provides customers with a superb balance of cost efficiency, efficiency and dynamics.
The combination of epicycle gear trains with a planet engaging both a sun gear and a ring gear is named a planetary gear train.[1][2] In this case, the ring gear is normally fixed and the sun gear is driven.