Abstract: A current feed extends between a terminal at ambient temperature and an electrical equipment immersed in a cryogenic fluid and adapted to operate at variable current. The current feed is cooled by circulating an auxiliary cooling fluid at ambient temperature exchanging heat with the current feed. The auxiliary cooling fluid is introduced at an intermediate level of the current feed when the current exceeds a particular threshold and optionally all or some of the auxiliary cooling fluid is introduced at other levels nearer the electrical equipment at higher currents.

Abstract: A superconducting static machine having a magnetic circuit includes a magnetic circuit core at mere ambient temperature and very low (cryogenic) temperature windings (1A, 1B) and one or more magnetic circuit cores at considerably higher temperatures. The magnetic circuit core is disposed in a thermally-insulating chamber (3) which is itself disposed inside a very low temperature (9) containing the windings. The invention is particularly applicable to transformers.

Abstract: Multifilament superconductor strands of less than 1 mm diameter able to carry alternating current are stranded to a pitch of between 7 and 3 diameters, at a temperature above 200.degree. C. and a speed between 30 and 5,000 rpm.

Abstract: In a heat pump, thermoelements (20,22) are disposed in a thermopile (P1) and are electrically connected in series. Heat is transferred horizontally from the thermopile and vertical air ducts (28) at its sides by suitable arms (42) prolonging heat conductors inside the thermopile. The arms or webs serve to convey heat to heat exchange fins. Application to domestic heating.

Abstract: The invention relates to a thermoelectric heat exchanger assembly including a liquid flow circuit. In a heat pump some of whose thermoelements (20,22) are disposed in a thermopile (P1), one of the heat exchange fluids is liquid and flows through the successive stages of the thermopile via a continuous metal tube (10) which has electrical resistance and is curved in a U configuration at each stage so as to increase the heat exchange area and to facilitate assembly. Application to domestic heating.