Abstract: An arrangement for electrically conductively connecting two electrical units by means of a bipolar high voltage direct current transmission, in which between the units are arranged at least two electrical direct current cables constructed as superconductive cables. The superconductive cables are mounted separately from each other in a cryostat (1,2) suitable for conducting a cooling agent which has at least one metal pipe provided with a thermal insulation. The cryostats (1,2) are connected with at least one of their ends to a cooling plant (7) supplying the cooling agent and a pipeline (3) is placed parallel to the two cryostats (1,2). The pipeline (3) is connected at both its ends to the two cryostats (1,2) through valves (15,16,17) which are closed during uninterrupted operation and, in the case of an interruption at one of the superconductive cables, the pipeline (3) serves with the then open valves for conducting the cooling agent intended for the cryostat of the impaired cable.

Abstract: A multi-bath apparatus and method for cooling a superconductor includes both a cooling bath comprising a first cryogen and a shield bath comprising a second cryogen. The cooling bath surrounds the superconductor, and the shield bath surrounds the cooling bath. The cooling bath is maintained at a first pressure and subcooled, while the shield bath is maintained at a second pressure and saturated. The cooling bath and the shield bath are in a thermal relationship with one another, and the first pressure is greater the second pressure. Preferably, the cryogens are liquid nitrogen, and the superconductor is a high temperature superconductor, such as a current limiter. Following a thermal disruption to the superconductor, the first pressure is restored to the cooling bath and the second pressure is restored to the shield bath in order to restore the superconductor to a superconductive state.

Abstract: A multiple circuit hybrid cryostat power lead has a plurality of laterally spaced, electrically isolated lead elements inside a tubular enclosure. Each lead element has an inner section with a high temperature superconducting (HTS) conductor inward of a divider in the tubular enclosure, and an outer normal conductor section outward of the divider. The outer sections of the lead elements have a pair of copper conductors spirally wound in an annular chamber between an electrically insulating central support and an electrically insulating sleeve to form helical flow passages. Cryogen vapor flows outward in the tubular enclosure inward of the divider over the HTS conductors, through a slotted heat exchanger electrically connecting the HTS and copper conductors at the divider, and through the helical flow passages to vents at outer terminals.

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: Apparatus and methods for cooling high temperature superconducting materials (HTSC) to superconductive temperatures within the range of 27.degree. K. to 77.degree. K. using a mixed refrigerant consisting of liquefied neon and nitrogen containing up to about ten mole percent neon by contacting and surrounding the HTSC material with the mixed refrigerant so that free convection or forced flow convection heat transfer can be effected.

Abstract: A device for cooling a SQUID measuring instrument for measuring biomagnetic or other weak magnetic fields includes a cryostat containing a vacuum in an interior space. At least one superconducting gradiomeer and at least one associated SQUID are disposed in the vacuum. Heat-conducting connections thermally couple the superconducting gradiometer and the associated SQUID to a cryogen supplied from outside the cryostat. A carrier structure supports the SQUID and the gradiometer. The carrier structure has cooling channels through which the cryogen is forced. A cryogen supply unit is situated outside the cryostat and a cryogen transfer line couples the cryogen supply unit to the cooling channels.

Abstract: The rotary dipole active magnetic regenerative refrigerator (10) of the present invention comprises a stationary first regenerative magnetic bed (12) positioned within a stationary first inner dipole magnet (14), a stationary second regenerative magnetic material bed (16) positioned within a stationary second inner dipole magnet (18), an outer dipole magnet (20) that rotates on a longitudinal axis and encloses the inner dipole magnets (14, 18), a cold heat exchanger (22), hot heat exchangers (24, 26), a fluid displacer (28), and connective plumbing through which a heat transfer fluid is conveyed.

Abstract: In a superconducting coil refrigerating method and a superconducting apparatus, a flow of liquid helium is induced in a helium vessel only at a specified time upon change of a current of the superconducting coil, before the current change and/or after the current change. The induction of the helium flow before the current change provides a condition that the transfer of helium gas bubbles which may be generated upon subsequent current change is rapidly effected. The induction of the helium flow upon the current change or after the current change results in the rapid exhaustion of helium gas bubbles which continue to generate or have been generated. With such a construction, even if a superconducting pulse magnet is used, any influence of helium gas bubbles produced due to an AC loss upon change of a current can be eliminated, thereby providing a coil which is stable to a pulse-excited magnetization thereof.