Abstract: The invention relates to a process for the preparation of a superconductor material of the mixed oxide type, such as oxides of the YBaCuO and Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8 type. This process consists of the deposition by electrolysis on a conductive substrate of successive layers of metallic elements entering in the constitution of the superconductor material, using a single element in each layer and carrying out, following the deposition of at least one of the layers, an intermediate oxidation-reaction heat treatment for fixing the element of said layer before depositing the following layer, optionally repeating one or more times at least part of the aforementioned operations, and subjecting all the layers to a final, oxidation heat treatment to form the mixed superconductor oxide.

Abstract: A ring designed to support instrumentation modules on the rotor of a rotary machine and to withstand centrifugal accelerations significantly in excess of 500 g comprises two half-rings made of zicral (AZ5GU) alloy clamped to the rotor shaft. In order for the ring to remain attached to the shaft at speeds up to and in excess of the maximum speed thereof, there are formed in the cylindrical perimeter of the ring a central groove and two side grooves. A tape of glass fibers impregnated with a polymerizable resin is wound on under tension in superposed layers, initially into the central groove and then into the side grooves. The wound tape is then immobilized under tension by polymerizing the resin.

Abstract: A current lead for a superconducting rotary machine is constituted by a copper tube having a superconducting conductor fastened (e.g. by soldering) to a portion of its length, the entire length of the tube having copper cooling plates each of which blocks the bore of the tube leaving only a small hole for the passage of gaseous or hypercritical helium. The current lead is particularly applicable to the generation of electric power using cryoalternators.

Abstract: The circulation of a low temperature cooling fluid is insured by thermal hon effect in a cryoalternator from within a closed loop circuit containing an inner rotating seal of the "bayonet" type with a very small radial gap. Longitudinal and radial piping within the rotor permits internal circulation of cooling fluid by thermal siphon effect across the "bayonet" type rotating inner seal in the absence of positive circulation by leakage of the coolant across the inner seal radial gap.