In this contribution, a novel multi-machine structure, called "Planetary Motor", is presented. It combines a multi-rotor electric motor with a planetary gear function. Compact drives are frequently built-up using a high-speed electrical motor, combined with a gear box for reducing angular speed. Motor and gear box are separate functional units, which can be constructed and operated seperately. The novel motor structure splits up the rotor in a multi-rotor arrangement which is mechanically coupled and interacting with a common winding system. After describing the motor structure, a control scheme is presented. The multi-rotor arrangement behaves like a single a.c. motor and can be supplied by a conventional inverter. The properties of the drive are explained and verified by a prototype. Further possibilities of modifying the structure are given.