Patent ID: 6046583
Filing Date: 2000-04-04
Classification: G01R,H01F

Abstract:
A crossed coil gauge comprising:a shaft oriented along a shaft axis;an oriented rare-earth magnet mounted to rotate with the shaft along the shaft axis, the magnet supplying magnetic flux directed transverse to the shaft axis, the magnet shaped as a cylinder having a maximum radius measured from the shaft axis and an axial length, wherein the length of the magnet exceeds the radius;a gauge housing which houses the magnet within a magnet cavity, the gauge housing providing support for rotation of the shaft and the magnet about the shaft axis,a first coil and a second coil each wound around the gauge housing, wherein the first coil is wound generally perpendicular to the second coil and wherein the first coil and the second coil encircle the magnet; anda flux ring, disposed around the first coil and the second coil and axially aligned with respect to the magnet and the shaft, said magnet having sufficiently high strength and said flux ring being mounted in sufficiently close proximity to the first and second coils to redistribute the magnetic flux supplied by the magnet such that the magnetic flux density near the first coil and the second coil is increased by at least 60% in comparison to the magnetic flux density supplied by the magnet without the flux ring.