In a flywheel energy accumulator comprising a vertical shaft rotatably supported in a vacuum housing by superconduct ive magnetic axial support bearings, lower and upper flywheels are mounted on the shaft in axially spaced relationship, a homopolar dynamic machine with a rotating magnetic field is disposed in the space between the flywheels and includes a stator supported in, or forming part of, the housing and a rotor mounted on the shaft so as to be disposed within the rotor, and the superconductive magnetic supporet bearings include a lower passive axial thrust bearing with an annular magnet disposed below the lower flywheel and an upper positive axial pull bearing with an annular magnet disposed above the upper flywheel and disc-shaped superconductors disposed adjacent the annular magnets such that both bearings provide magnetic forces jointly counteracting the gravity forces of the shaft, the rotor and the flywheels.

A high temperature superconductor material bearing system (38) This system (38) includes a rotor (50) having a ring permanent magnet (60), a plurality of permanent magnets (16, 20 and 70) for interacting to generate levitation forces for the system (38). This group of magnets are a push/pull bearing (75). A high temperature superconductor structure (30) interacts with the ting permanent magnet (60) to provide stabilizing forces for the system (38).

In a flywheel energy accumulator including, in a vacuum-tight housing, a vertical shaft with a rotor of an electric motor/generator arranged in the axial center of the shaft and flywheels mounted on the shaft at opposite sides of the rotor, the electric motor/generator and the flywheels are included in modules, each with a housing ring, which are mounted on top of one another and receive bearing modules including support discs mounted between, and adjacent, the housing rings with superconductive magnetic bearings disposed in the center thereof around the shaft for supporting the shaft with the flywheels and the rotor. The number of superconductive bearings is twice the number of flywheels. The bearing module discs between adjacent flywheels have upper and lower superconductive magnetic bearings and the bearing modules at the axial ends of the shaft and adjacent the rotor carry each only one superconductive magnetic bearing so that the number of superconductive magnetic bearings is greater, by two, than the number of flywheels.

A high temperature superconductor bearing is disclosed which provide a strong levitation force and thus enable the construction of a horizontal-axle flywheel energy storage system. The bearing includes a magnet journal made of high temperature superconductor films, and a stator formed of a plurality of high temperature superconductors installed opposite to the high temperature superconductor magnet journal or the magnet journal for thereby off-setting the force such as the weight applied to the rotor using a magnetic pressure.

An energy storage device which comprises at least a first object having a rotational mechanism which rotates around an axis and a surface which generates a magnetic field; at least a second object comprising a superconductor and having provided separately from said first object but facing said surface which generates a magnetic field; a device which provides a rotational energy to the first object by exerting an electromagnetic reaction to said first object; and a device which converts the rotational energy of the first object into an electric energy; provided that the first object is substantially levitated at its use, and that said first object uses no mechanical support device. Also claimed are methods of converting energy, which comprise a method of converting an electric or a magnetic energy into a kinetic energy, and a method of converting a rotational energy into an electric energy, said methods taking advantage of flywheels being supported by levitation resulting from the interaction between a magnetic field and a superconductor, and not by a mechanical supporting device.