Abstract: A superconducting current limiting apparatus includes a first container, a superconducting current limiting element accommodated in the first container, a refrigerant filling the first container for cooling the superconducting current limiting element accommodated in the first container, a second container for accommodating the first container in such a manner that the first container is heat insulated, and a conductor for connecting the superconducting current limiting element to an external power supply system. Such a superconducting current limiting apparatus can be used to limit a short-circuit current. It can be incorporated in a short circuit controlling superconducting system.

Abstract: A superconducting magnet apparatus comprising a superconducting main coil (1) for generating a uniform magnetic field and at least one superconducting shim coil (2a, 2b) electromagnetically coupled to the superconducting main coil (1) for increasing the uniformity of the magnetic field generated by the main coil (1). An emergency run down main coil heater element (21) is disposed adjacent to the main coil (1) for demagnetizing the latter, an emergency run down shim coil heater element (22a, 22b) is disposed in proximity of the shim coil (22a, 22b) for demagnetizing the latter, and a heater power source (24) is provided for supplying an electrical power to the heater elements (21,22a,22b). A switching unit (25,26,27) is connected between the heater elements (21,22a, 22b) and the heater power source (24) for connecting the heater power source (24) to the shim coil heater element (22a, 22b) and to the main coil heater element ( 21) at different time points with a predetermined time interval therebetween.

Abstract: A CMOS circuit including a variable conductor means interposed between a power supply and the CMOS circuit. The CMOS circuit comprises a P channel MOS FET and an N channel MOS FET laterally formed on the surface of a semiconductor substrate, inherently producing a parasitic thyristor which can be latched-up with destructive consequences under certain circumstances. The variable conductor means, interposed between the power supply and CMOS circuit, preferably includes a superconductor arranged to sharply switch to a normal conductor mode when the current level exceeds a critical current level, established to be less than the latch-up holding current of the parasitic thyristor, thereby to prevent latch-up.

Abstract: A current limiter comprising a cryostat provided with a first insulating feedthrough for an inlet conductor and a second insulating feedthrough for an outlet conductor, and a conductor running from one feedthrough to the other inside the tank, said conductor being constituted at least in part by a superconducting material, the cryostat being filled with a fluid at a temperature which is low enough to maintain said material in the superconducting state, said portion made of superconducting material including at least one portion comprising superconducting wires (7, 8) wound in opposite direction windings on two coaxial insulating formers (14, 15). Respective the ends of each of the superconducting wires (7, 8) are connected firstly to the inlet conductor and secondly to the outlet conductor via identical elementary current feeds (21A, 22A).

Abstract: Magnet coil system for nuclear spin tomography has superconducting coils for generating a homogeneous magnetic base field and nonsuperconducting coils within an interior region defined by the base field coils for developing magnetic field gradients. At least one cooled radiation shield of electrically and thermally conductive material is arranged between the gradient coils and the superconducting base field coils. To prevent eddy currents started in the radiation shield from distorting the gradient fields, the radiation field contains superconducting material of a "second kind" that is a high temperature superconductor. The superconductor is in a nonsuperconducting state at the start of an excitation process for the base field coils and in a superconducting state during the undisturbed operation of the magnet coil system.