GB1368614A - Pulse generator - Google Patents

Abstract

1368614 Permanent magnet generators J R WIEGAND and M VELINSKY 19 Nov 1971 [19 Nov 1970] 53865/71 Heading H2A A pulse generator comprises a wire 20 having two layers of different magnetic properties, the two layers initially being magnetized in the same direction, the direction of magnetization of one layer then being reversed, this latter change producing a pulse in a sensor. The rotary pulse generator disclosed comprises a rotatable plastics support 13 having on its periphery a plurality of equally spaced wires 20, each wire having a core of coercivity and retentivity lower than those of an outer shell portion. A stator unit 40 comprises a coil 54 mounted on a magnetic core 46 disposed between two permanent magnets 60, 62 which are arranged to produce magnetic fields of opposite polarity on opposite circumferential sides of the core. When each wire enters one field its core and shell are magnetized in the same direction and when the wire leaves that field, the shell remains permanently magnetized and uses the core as a flux return path, this change in direction of magnetization of the core producing a flux change in the magnetic core 46 which produces a pulse in coil 54. The other of the two magnetic fields adjacent the core 46 is effective for the other direction of rotation of support 13. The shells of the wires may additionally be premagnetized by a permanent magnet 80 or 82 (depending on the direction of rotation of the support).