Abstract: The invention relates to a device (40) for magnetically axially supporting a rotor, which rotor comprises a thrust bearing plate (32) connected to the rotor, in a magnetic thrust bearing (54) having at least two independently controllable bearing branches (3, 4, 41) which each comprise at least one coil (5, 42), wherein magnetic flux isolation of the bearing branches (3, 4, 41) is provided, which flux isolation consists in that at least two of the bearing branches (3, 4) are arranged one after the other in the circumferential direction and have a single common pole (9) which has a circularly closed circumference, the center point of which is arranged on the axis of rotation (35) of the rotor, wherein the coils (5) surround pole segments (11) connected to the common pole (9) and wherein the common pole (9) is arranged either radially inside or radially outside of the pole segments (11), and/or in that the thrust bearing plate (32) is divided into at least two coaxial plate parts (46, 61) which are associated w

Abstract: Disclosed is a flywheel (13) comprising a rotating element (13?) which rotates in relation to an axis of rotation and includes a radially outer flywheel mass member (24) that adjoins an inner shaft connection part (26) and tapers in the radial direction such that hollow projecting end pieces (24?) are formed. The external face of the outer flywheel mass member (24) has a radial indentation (25) that extends all around the flywheel mass member.