GB816714A - - Google Patents

Abstract

816,714. Electric transducers. SPERRY GYROSCOPE CO. Ltd. Feb. 15, 1957 [Feb. 24, 1956], No. 5814/56. Class 40 (1.). A pick-off for measuring linear displacement comprises a stator consisting of two ferromagnetic laminations 1, 2 (Fig. 1) each having diametrically opposite salient poles 3, 4 and 5, 6 respectively located at 90 degrees to each other, and a ferro-magnetic armature 7 located centrally on a rod 8 movable axially, the four poles 3-6 being surrounded by an A.C.-energized primary winding 9 (Fig. 2) one half of which surrounds poles 4, 6, the other half surrounding poles 3, 5, and also by a secondary winding 10 also wound in two halves, one half surrounding poles 4, 5, and the other half surrounding poles 3, 6. The flux through coil 10 is therefore in one direction when the armature 7 closes the gap between poles 3, 4, is in the other direction when the armature closes the gap between poles 5, 6, and is zero when the armature 7 is centrally located with respect to the poles 3-6. Hence the phase of the voltage in winding 10 is indicative of the direction of axial displacement of rod 8 and armature 7 from the central position, and the magnitude of the voltage is indicative of the extent of linear displacement. In another embodiment (Fig. 6) the stator may be crossed laminations 15, 16 and the armature 19 consists of a surrounding ring lamination. Several units may be clamped together to increase the output signal, and the rod 8 may be provided with a key-way to prevent rotation.