Abstract: A magnetic resonance apparatus comprises a magnet system for generating a magnetic field in a working volume. Magnetic gradient coils are used to generate one or more magnetic field gradients in the working volume so as to define regions from which magnetic resonance signals are obtained from a target material. A controller operates the gradient coils in use so as to apply one or more magnetic field gradients within each region. For each of the defined regions, the controller performs a method in which the one or more magnetic field gradients are controlled in accordance with the position of the said region with respect to the gradient coils, such that the one or more magnetic field gradients have a predetermined uniformity, thereby increasing the uniformity within regions at the periphery of the working volume.

Abstract: An apparatus for magnetic resonance imaging includes a first magnet for generating a first magnetic field and a second magnet for generating a second magnetic field, dissimilar to the first magnetic field, the second magnet being spaced apart from the first magnet. The apparatus is arranged such that the first and second magnets cooperate to generate a substantially homogeneous magnetic field defining a working region wherein the first and second magnetic fields are arranged asymmetrically with respect to the working region, and wherein at least part of the working region is positioned within the first magnet or between the first and second magnets.

Abstract: The present invention relates to an electrical transformer which includes a primary winding coupled to first and second magnetic circuits. A magnetic flux is driven through the magnetic circuits by the primary winding. First and second secondary windings are also provided, each associated with a respective one of the magnetic circuits and being electrically connected together in series opposition. A closed superconducting fault current winding is also provided to link with the magnetic flux in the second magnetic circuit.

Abstract: The present invention relates to an electrical transformer which includes a primary winding coupled to first and second magnetic circuits. A magnetic flux is driven through the magnetic circuits by the primary winding. First and second secondary windings are also provided, each associated with a respective one of the magnetic circuits and being electrically connected together in series opposition. A closed superconducting fault current winding is also provided to link with the magnetic flux in the second magnetic circuit.

Abstract: The present invention relates to an electrical transformer which includes a primary winding coupled to first and second magnetic circuits. A magnetic flux is driven through the magnetic circuits by the primary winding. First and second secondary windings are also provided, each associated with a respective one of the magnetic circuits and being electrically connected together in series opposition. A closed superconducting fault current winding is also provided to link with the magnetic flux in the second magnetic circuit.

Abstract: A current limiting device comprises a first superconducting element for connection in an electrical circuit. The superconducting element has a critical current density. A second superconducting element detects the onset of a fault condition. A coil is responsive to the second superconducting element to vary the relationship between the critical current density and the current carried by the first superconducting element so that the element transforms into a resistive state.

Abstract: A current limiting device having an electrical superconductor for attachment in an electrical circuit, the superconductor being made of material having a critical current density which varies with applied magnetic field. A magnetic field generator generates a magnetic field to which the superconductor is exposed. Under normal working conditions a magnetic field applied causes the critical current density to be less than a maximum critical current density. A controller adjusts the critical current density such that after a current carried by the superconductor exceeds the critical current density so that the superconductor transforms to a resistive state, the controller can be activated to increase the critical current density causing the superconductor to return the superconducting condition without terminating the flow of current through the superconductor.

Abstract: A nuclear magnetic resonance apparatus having a magnetic assembly which generates a main static field in a working region which is external of the magnetic assembly. The main static magnetic field has a uniformity suitable for performing NMR experiments. An oscillating magnetic field generating assembly is provided with a set of axially aligned electrical coils connected to an oscillating electrical source. The axially aligned electrical coils generate an rf magnetic filed within the working region of the magnet assembly. Adjacent coils of the axially aligned electrical coils are wound in opposite senses and connected in series so as to generate opposing magnetic fields which superimpose to produce an oscillating magnetic field external of the magnet assembly. The oscillating magnetic field is sufficiently uniform within the working region to perform NMR experiments.