Abstract: In a gear which can be flanged onto an electric motor, especially a low-clearance planetary gear, with a hollow shaft to make a positive connection with the electric motor output shaft, an easily manufactured and reliable centering system is to be provided between the gear and the electric motor (6). To this end, the section of the hollow shaft (9) accepting the output shaft (10) of the electric motor is centrically secured on roller bearings (11) and the face of the drive flange is radially freely centerable (7, 8) in relation to the mating surface of the electric motor. To enable a drive with as uniform a basic structure as possible to be connected to electric motors with different connecting geometries, the gear has an interchangeable mating plate (2) forming its connecting flange and a hollow shaft into which compensating sleeves (12) can be inserted to accept electric motor output shafts of different diameters.