Abstract: The invention relates to a resistive current limiter having at least one conductor of a superconductive high-temperature material, carrying the rated current. The electrically active length of said conductor is at least three times greater than its linear extent.

Abstract: A device for inductive current limiting of an alternating current consisting of an induction coil (2), which includes at least one winding and through which current flows, a body (3) made of a ceramic high-temperature superconductor arranged concentrically to the latter and having a centrosymmetrical form which is hollow in the interior, and having located in the interior of said body (3) a concentrically arranged core (4) made of a soft magnetic material of high permeability. In normal operation (rated current), the superconductivity of the body (3) is effective and impedance of the induction coil (2) is very low. With overcurrent (mains short-circuit) the superconductivity disappears and the impedance of the induction coil (2) reaches its maximum, current-limiting value.

Abstract: An arrangement of electrically anisotropic high-temperature superconductors (A1, A2) on a non-superconducting metal strip (1) for alternating-current applications, such as magnets and electrical machines, is specified in the case of which a relatively simple reduction of alternating-current losses is achieved in that at least one strip (A1, A2), deposited as a layer, made of a high-temperature superconductor, spirally surrounds this metal strip. The superconducting strip (A1, A2) has a preferred direction in which the critical current density is smaller than in all other directions. In this arrangement, a current (i) flowing through the superconductor flows periodically through regions of the superconductor (A1, A2) that are oriented in the preferred direction and twisted by 180.degree. thereto. These periodic regions limit the length of the eddy currents.

Abstract: Electrical conductor in wire or cable form composed of a sheathed wire or of a multiple-filament conductor based on a ceramic high-temperature superconductor of the REBa.sub.2 Cu.sub.3 O.sub.6.5+y type, RE being=rare-earth metal, O<y<1, or of the (La,Ba,Sr).sub.2 CuO.sub.4 type, as core (1) and of a metal sheath (3) as mechanical support and emergency current conductor, the core (1), clad with metal sheath (3), of each filament of the electrical conductor composed of a multiplicity of filaments being embedded on all sides in a soft magnetic material (4) of high permeability.