Abstract: Method of maintaining a superconducting cryolink at low temperature by a flow of liquid nitrogen produced by a liquefier feeding one end of a link section, wherein the section is fed by a single liquefier and nitrogen is drawn off from at least one intermediate point of the link section.

Abstract: Protection means (6, 18) are associated with the radiating system (16) of a transmitter constituting a radiotelephone (4). The purpose of the protection means is to reduce the amount of radiation that is intercepted, i.e. the proportion of the emitted radiation (20) that is intercepted by the body of the user (2), so as to enable the overall power of the radiation to be increased. In accordance with the invention, said protection means include a casing (18) ensuring that safe distances (33, 34, 35) are maintained between the radiating system and the body of the user. The protection means further include a screen (6) that absorbs the radiation. The invention applies in particular to long-range radiotelephones.

Abstract: A toroidal hybrid transformer includes a primary winding (2), which is superconducting in operation and a secondary winding (10) which is non-superconducting, separated by thermal and electrical insulation. A strength member (1) withstanding the centripetal forces exerted on the primary winding supports the primary winding (2) and is disposed inside the conductor turns (20, 21; 26, 27, 28) constituting the primary winding. Anchoring wedges (3, 12) mechanically couple the strength member to at least that portion of each of said conductor turns which is adjacent to the axis of symmetry (14) of the toroidal transformer, thereby transmitting the centripetal forces exerted on the primary winding to the strength member.

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: An electric rotating machine whose inductor operates at very low temperat and is separated from the rotor by an empty space, characterized in that a reflector screen constituted by a layer of thermally conductive strips connected together at their axial ends by thermally conductive connection parts to a cooled structure, is inserted in that empty space.