Abstract: A method for the calculation of an output spectrum of a matrix converter in which m phases of a generator as an input are alternatingly connected via a multiple number of controllable bi-directional switches arranged in an (m×n) matrix with n (n<m) phases of a load as an output. An assessment of the spectrum to be used, for example, for compensation of harmonic distortions of the output spectrum can be obtained by calculating the electromotive force spectrum based on at least one of the connectivity of the phases, on the phase relationship between input and output, and on the instants when commutations of the switches are initiated and on the instants when commutations of the switches are completed.

Abstract: A method for operating a matrix converter in which m phases of a generator generating alternating voltage with n (n<m) phases of a load are alternatingly connected via a multiple number of controllable bi-directional switches arranged in an (m×n) matrix, wherein switching over from a selected connected phase of the generator to a selected non-connected phase of the generator takes place in a controlled sequence of commutation instants of the individual switches.

Abstract: A rotor for electrical rotating machines includes a rotor core with axial grooves for receiving axial conductors. A first element on the axial grooves and a corresponding second element on the axial conductors interact with one another to fix the axial conductors in the axial grooves in particular with respect to centrifugal and torsional forces. The provision of structural features on the rotor in the grooves and corresponding features on the conductors allows a simple and direct assembly of the conductors to the rotor core without additional fixing means. A method of assembling such a rotor is also provided.

Abstract: A very simple and reliable rotor (4) for a (brushless) exciter to be used to energise the field winding of a rotor of a generator, is proposed which can be used for high-speed rotation and for the generation of high currents for energising the field winding of the rotor of the generator. The rotor (4) comprises at least two conducting bars (6) aligned substantially parallel to the axis (8) of the rotor (4), wherein the bars (6) are connected on their first axial end to a collecting ring (13) and wherein on their second axial end the bars (6) are connected individually to two rings (14, 15) by means of diodes (16) with reversed polarity such that alternating current induced in the conducting bars (6) due to a static field (7) is converted into a direct current (DC) in the two rings (14, 15).

Abstract: A very simple and reliable process for cancelling the reaction field (10) induced by a rotor (4) is proposed, wherein the rotor (4) is rotating in a static magnetic field (7) in a static outer core (3), and wherein the rotor (4) comprises at least two conductors (6) aligned substantially parallel to the axis (8) of the rotor (4). The armature reaction (10) is cancelled by means of a set of auxiliary windings (11) located on the static outer core (3) wherein said auxiliary windings (11) are fed with a direct current (DC) cancelling the reaction field (10). Preferentially, the process is applied to a brushless exciter and the auxiliary windings (11) have the same geometry as the conductors (6) of the rotor (4) and are all equally fed with a direct current corresponding to the current induced in the conductors (6) of the rotor (4) when the rotor is rotating in the static magnetic field (7).

Abstract: A very simple and reliable rotor (4) for a (brushless) exciter to be used to energise the field winding of a rotor of a generator, is proposed which can be used for high-high speed rotation and for the generation of high currents for energising the field winding of the rotor of the generator. The rotor (4) comprises at least two conducting bars (6) aligned substantially parallel to the axis (8) of the rotor (4), wherein the bars (6) are connected on their first axial end to a collecting ring (13) and wherein on their second axial end the bars (6) are connected individually to two rings (14,15) by means of diodes (16) with reversed polarity such that alternating current induced in the conducting bars (6) due to a static field (7) is converted into a direct current (DC) in the two rings (14,15).

Abstract: In a method for operating a matrix converter (10) in which m phases (G1, . . . ,G6) of a source (11) delivering an alternating voltage are alternatingly connected with n phases (L1, . . . ,L3) of a load (12) via a multiple number of controllable bi-directional switches (14) arranged in an (m×n) matrix, an increased performance at decreased expenditure becomes possible in that switching over from a first phase (G1) of the source (11) to a second phase (G1) of the source (11) only takes place if the condition Ik·(Vk−Vl)·Kijkl<0 is met, where Ik and Vk are the current and the voltage of the first phase (G1), Vl is the voltage of the second phase (G1) and in each instance Kijkl is a characteristic constant for the mutual inductance between the phases (G1, . . . ,G6) of the source (11) and the inductance of the load (12).

Abstract: In a method for operating a matrix converter (10) in which m phases (G1, . . . ,G6) of a source (11) delivering an alternative voltage are alternatingly connected with n phases (L1, . . .

Abstract: A superconductive conductor protected against partial transitions, the conductor comprising a superconductive region made up of superconductive filaments embedded in a non-superconductive metal matrix, and a non-superconductive metal region, wherein the cold resistivity of the non-superconductive metal region is less than half the overall cold resistivity of the superconductive region in the non-superconductive state, the superconductive region and the non-superconductive metal region being merely in mechanical contact, without cohesion.

Abstract: The present invention relates to a superconductive coil assembly which may be used particularly for a current limiter, the coil assembly comprising a plurality of coaxial cylindrical coils electrically connected in series, each coil comprising two windings of superconductive material electrically connected in parallel, arranged coaxially and wound in opposite directions, wherein in each coil, the windings are separated by a material which has a surface resistance in the radial direction lying in the range 10.sup.-5 .OMEGA..m.sup.2 to 10.sup.-2 .OMEGA..m.sup.2 at the temperature of the cryostat, and in which the strands which constitute the superconductive wires may themselves be covered with a layer of the same material.

Abstract: A superconductor protected against partial transition includes superconductor strands around at least one non-superconductor central strand or at least one non-superconductor central core electrically insulated from the superconductor strands. At least at both ends of the superconductor, the central strand or said central core is electrically connected to the superconductor strand. The central strand or the central core comprises at least one non-superconductor metal filament whose resistivity at 4.2.degree. K. is less than 10.sup.-9 .OMEGA..m embedded in a metal alloy matrix whose resistivity at that temperature is greater than 10.sup.-8 .OMEGA..m.