Improvements in or relating to the Determination of the Direction of Magnetic Fields.

摘要

1,168,678. Determining direction of magnetic field. P.B. FELLGETT. March 11, 1968 [March 14, 1967], No. 11840/67. Heading G1N. Apparatus for determining the direction of a magnetic field comprises a slotted cylindrical conductive member 1, Fig. 1 rotated about its longitudinal axis by air thrust at air bearings 3, 4, whereby the member acts as a single turn coil and an induced current flows round the slot to produce an alternating magnetic field which is sensed by surrounding quadrant coils 5a-5d, to produce AC voltage signals which are used to line up the rotation axis with the field direction. The slot 2 is preferably perpendicular to the axis of the rotor 1. The angular position of the rotation axis when the signals in coils 5a-5d have been eliminated, i.e. when it coincides with the direction of the magnetic field, is measured by known means relative to the vertical and North. The rotating member may have a high permeability core surrounded by a coil whose induced c.m.f. is indicative of the angle between the magnetic field and the axis of rotation. The rotating member may alternatively carry an electromagnet or permanent magnet, with a total-field magnetometer on the rotational axis, which senses when the axial total field strength is constant during rotation, indicating coincidence between the axis of rotation and the direction of the external magnetic field.