Abstract: A method and apparatus for field weakening in PM machines uses field weakening coils (35, 44, 45, 71, 72) to produce flux in one or more stators (34, 49, 63, 64), including a flux which counters flux normally produced in air gaps between the stator(s) (34, 49, 63, 64) and the rotor (20, 21, 41, 61) which carries the PM poles. Several modes of operation are introduced depending on the magnitude and polarity of current in the field weakening coils (35, 44, 45, 71, 72). The invention is particularly useful for, but not limited to, the electric vehicle drives and PM generators.

Abstract: A device for determining rotary motions generally includes a signal generator with inwardly directed teeth or inwardly directed projections and a double-sided measuring coil which is arranged within the surface of the signal generator. The measuring coil has a core of permanent magnets and pole shoes. The pole shoes project from both sides of the coil and extend up to the inner surface of the signal generator. The pole shoes are designed, arranged and conformed to one another so that, whenever the end piece of a pole shoe points to a tooth or a projection, the second, diametrically opposite end of the pole shoe is directed to a tooth gap or depression. The measuring coil core is made up of at least two permanent magnets which are magnetized perpendicularly to the coil axis and respectively embedded between two pole shoes.

Abstract: An electrical generator has a plurality of C-shaped stator members which are made of magnetically permeable material. Each C-shaped stator member includes a respective stator winding, and the stator members are positioned such that the ends of the members form first and second planar rings of equal diameter to establish a gap therebetween. A flat, ring-shaped rotor defines a periphery, and a plurality of permanent magnets are positioned around the periphery. The rotor is positioned with the magnets of the rotor disposed in the gap defined by the stator members. Consequently, when the rotor is rotated by a prime mover to move the magnets through the gap, an electrical current is induced in the stator windings.

Abstract: A rotational velocity sensor ring comprising a circular cylindrical body with a radially interior cylindrical surface, a radially exterior cylindrical surface and first and second cylinder ends, a plurality of substantially equally spaced, substantially equal length fingers extending from the first cylinder end, and on each of the fingers, a substantially 180.degree. bend proximate to the first cylinder end, wherein each finger is radially exterior of the circular cylindrical body, wherein each finger has a finger end extending toward a second cylinder end opposite the first cylinder end, wherein each finger is proximate to the radially exterior cylindrical surface and parallel to a cylinder axis of the circular cylindrical body, wherein the fingers comprise a set of teeth of the rotational velocity sensor ring.

Abstract: A device for measuring rotary motions having a signal generator ring which rotates with the rotating part and of a double-sided measuring coil. Within the core of the measuring coil there are a permanent magnet, which is magnetized perpendicularly to the coil axis, and two elongated pole shoes which are arranged on the pole surfaces of the permanent magnet and whose end pieces protrude from both sides of the coil and reach almost as far as the signal generator ring. The signal generator ring and the pole shoes are designed, arranged and attuned in respect of one another so that, during the rotary motion, the magnetic flux alternately passes via the end piece of one pole shoe to the end piece of the pole shoe arranged on the second pole surface, which end piece protrudes from the other side of the coil, and thereupon passes via the two other end pieces of the pole shoes. Provided as signal generator ring is a toothed wheel with inwardly directed teeth or several toothed wheels firmly coupled with one another.

Abstract: The sensitivity of an induction-type motion sensor having a magnetic circuit with a permanent magnet to small movements is increased by the use of a stator with a core containing a permanent magnet as a fixed part thereof. An electrical coil is wound around the stator and a pendulum-type rotor has a ferromagnetic moving element which, when the motion sensor is subjected to movement forces, passes in and out of the air gap of the stator, thereby alternating the magnetic field in the stator and inducing a current in the electrical coil.

Abstract: A variable reluctance drive system including a motor and corresponding converter for improved current commutation is described. The motor incorporates a salient pole rotor and a salient pole stator having one or more full pitch windings which operate by mutual inductance to transfer the current from the active short pitch winding following phase alignment. This increases output torque and/or speed and permits a number of simple and economical converter circuits.

Abstract: A vehicle wheel speed sensor incorporated on an axle spindle hub and hub cap assembly of the type using permanent magnets to generate a magnetic field having a magnetic path conducted through a plurality of teeth on a flange extending from the hub cap into a plurality of teeth on a stator with relative motion therebetween upon rotation of the wheel where the frequency of the change in the magnetic reluctance varies at a frequency proportional to the wheel speed. The stator is mounted to the end of the axle spindle by a securing bolt so that the stator can be easily removed for service without disturbing the axle bearings. As a part of the stator assembly, a locating plate is provided which allows the operating gap between the teeth formed in the flange and the teeth formed in the stator to be easily established upon assembly of the hub cap to the wheel hub by allowing the rotor to contact the locating plate when the hub cap securing bolts have been loosened and the axle is supported.

Abstract: A vehicle wheel speed sensor of the type using permanent magnets to generate a magnetic field having a magnetic path which is conducted through a plurality of teeth on a rotor into a plurality of teeth on a stator with relative motion therebetween where the frequency of the change in the magnetic reluctance varies at a frequency proportional to the wheel speed. The stator is mounted to the end of the axle spindle by way of a securing bolt so that the stator can be easily removed for service without disturbing the axle bearings. As a part of the stator assembly, a locating plate is provided which allows the operating gap between the rotor and the stator to be easily established upon assembly of the hub cap to the wheel hub by allowing the rotor to contact the locating plate when the hub cap securing bolts have been loosened and the axle is supported.

Abstract: A d.c. motor unit with a rotational speed detector comprising a d.c. motor (1) having an output end and an idle end, and a rotational speed detector (14) water-tightly attached to the motor output end. The d.c. motor (1) comprises a motor frame (2) including an output end and an idle end, a mounting bracket (9) attached to the output end of the motor frame (2) and a rotary shaft (4) having an idle end rotatably supported by the motor frame (2) and an output end rotatably supported by and extending outwardly through the mounting bracket (9). The rotational speed detector (14) comprises a rotary portion mounted on the output end of the rotary shaft (4) and a stationary portion mounted to the mounting bracket at the output end of the motor frame (2). The rotational speed detector (14) comprises a substantially elastic permanent magnet plate (20) for generating a magnetic flux (.phi.

Abstract: A variable reluctance motor (10, 100, 200) for providing holding torque in accordance with the invention includes a magnetically permeable rotor (12); a stator (18) axially aligned with the rotor having at least one phase winding (22) for producing a magnetic field causing the rotor to rotate; and a first cylindrical magnet (26) mounted coaxial with and outboard from a first side of the rotor which creates a permanent magnetic field coupling the rotor to the magnet to provide holding torque.

Abstract: A Wiegand-effect shaft position sensor is excited by an alternating magnetic field generated by stationary magnets or solenoids interacting with a high-strength, toothed wheel that is fixed to the rotor. A set of three stationary poles are situated proximate to the rotor and are connected together by a yoke. The magnets or solenoids are mounted in the outside poles of the set of three stationary poles. The central stationary pole contains a Wiegand-effect device. In operation, a flux reversal in the Wiegand-effect device occurs at twice the frequency at which the poles of the toothed wheel pass the stationary poles, resulting in the generation of sharp voltage pulses indicative of rotor position.

Abstract: A current carrying drive coil in a magnetic field is moved by the field. An attached tachometer coil, passing through the same field, produces a voltage from which the speed of the coils may be calculated. Changes in the drive coil current produce noise in the tachometer coil. This noise is offset by combining the tachometer voltage with the voltage produced by a stationary pickup coil, which picks up only the noise.

Abstract: A variable reluctance rotation sensor comprises a rotatable magnetic toothed wheel adjacent a fixed magnetic pickup assembly. The pickup assembly comprises a pair of permanent magnets, each with a similar pole adjacent the wheel and separated circumferentially by the arc between a tooth and a non-adjacent slot. A magnetic flux member with a coil joins the other poles of the magnets in series opposed relationship and extends in close proximity to the tooth wheel to establish separate flux loops for each magnet distributed along the coil. The flux loops are spatially determined by the teeth and slots between the permanent magnets, so that they fluctuate circumferentially and generate an electrical signal in the coil with wheel rotation by variation of the flux linkages to individual turns of the coil. The sensor thus uses spatial flux changes to produce a rotation signal at very low rotational speeds with a larger air gap than that of conventional sensors.

Abstract: A variable reluctance rotation sensor comprises a rotatable toothed wheel and a magnetic pickup assembly comprising a pair of permanent magnets each having a pair of poles with an opposite one of said poles adjacent the toothed wheel. The permanent magnets are separated from each other by an arc equal to the arc between two of the teeth and joined by a magnetic flux member with a multi-turn electrical coil wound thereon. The flux member establishes a common main flux loop through the first and second permament magnets but also extends close to the toothed wheel to further establish additional flux loops separately through each of the permanent magnets. Passage of alternating teeth and slots as the wheel rotates produces a spatial fluctuation in the additional flux loops between the magnets to vary the flux linkages with individual coil turns and increase the electrical signal in the coil over the signal level that would be produced by variations in air gap of the common flux loop alone.

Abstract: An electromagnetic pickup has a coil and a core. A noise shielding cylindrical member of magnetic material is provided around the coil to form an open magnetic circuit between the noise shielding member and the core.

Abstract: A tachometer device having a sensor generating an electrical signal at a frequency which is proportional to a speed to be detected, an operating drive member, and electrical link means connecting the sensor to the operating drive member. A device for limiting frequency variations in the pulses applied to the operating drive member is interposed between the sensor and said operating drive member.

Abstract: A pulser ring has cylindrical inner and outer rings nested together. The inner ring is formed at its one end with protrusions arranged at equal angular intervals. The outer ring is in the shape of a round comb and has its teeth engaged at a portion near the tip thereof in the grooves defined between the adjacent protrusions formed on the inner ring. The tip of each tooth protruding from the grooves is bent radially inwardly so as to engage the end face of the protrusion on the inner ring, thus coupling the inner ring and the outer ring together.

Abstract: A dual speed sensor pickup assembly (140) for sensing the rotational velocity of two independently rotatable, closely axially spaced exciter rotors (116 and 118) is provided. The pickup assembly includes two speed sensor assemblies (136 and 138) each including a pole piece (152,160) having a longitudinal axis (152a,160a) with the longitudinal axes skewed relative to one another but radial relative to the common axes of rotation (24) of the exciter rotors. Each speed sensor includes a permanent magnet (154,162) disposed between an end of the pole piece (152,160) and having a face divided into first and second surfaces (154a,154b and 162a,162b) by a slot (154c,162c) therein. In one embodiment a primary coil (156,164) and a secondary or anti-cross talk coil (158,166) surrounds the pole piece of each sensor (136,138), and each secondary coil is conductively connected to the primary coil of the other sensor.

Abstract: A tachometer generator of the inductive pickup variety is disclosed, particularly adapted to be mounted in close proximity with a rotating multipole permanent magnet structure. The coil produces a voltage output proportional to the rate of change and magnitude of the magnetic flux of the rotating magnet. In accordance with this invention, an inductive pickup is disclosed having a core piece which acts as a conduction path for the magnetic field of the rotating magnet and further acts as a means for mounting the inductive pickup within the associated structure. Lead wires are imbedded within the bobbin and form protruding central conductors which act as posts to which each end of the coil wires are electrically and mechanically attached. The lead wires and core piece components are insert molded such that they are loaded into an injection molding die prior to the introduction of plastic material in a molten state which forms the bobbin component.

Abstract: The invention provides an iduction generator comprising a plastic injection-molded housing having a port and one or more pole shoe(s) associated with a permanent magnet. A plastic bobbin inserted into the port and having a coil wound thereon which, through soldering eyelets, is connected to two contact tags in communication with an outwardly guided cable. A mounting member, with the port at the end thereof facing the soldering eyelets being closely sealed by a lid welded to the housing.To provide an induction generator that is easy to manufacture and that insures a substantially improved operation, the port of the housing at the end thereof facing away from the soldering eyelets is closed by a bottom integrally formed with the housing and the pole shoe or shoes along with the associated permanent magnet are integrated in the housing.

Abstract: A speed and torque sensor has a permanent magnet and a pole piece about which are wound together a torque coil and two speed coils and identical with the torque coil. The coils and permanent magnet assembly are contained in an outer housing together with resistors and connected in series with the respective speed coils. The resistance of the resistors and is approximately fifty times that of the speed coil and so that shorting of the output of a speed coil beyond the resistor does not substantially increase current drawn by the coil. A temperature sensor in the housing enables compensation for changes in temperature on modulus of elasticity of the member subject to torque.

Abstract: A bearing assembly comprising a bearing including an inner and outer rings one of which is fixed to a rotating member, and a pulser gear fixed to the rotating member. The pulser gear is composed of an annular magnetic plate member and having a plurality of punched through holes mutually separated along a circumferential direction thereof. Revolution of the rotating member can be detected by a sensor provided close to the pulser gear.

Abstract: The invention relates to improvement of a motor with a rotor including a permanent magnet. The motor comprises a yoke of soft magnetic material, a plurality of field poles each having a field core of semi-hard magnetic material and a pole piece of soft magnetic material, a plurality of coils wound around the field cores respectively, and a rotor including a permanent magnet. In this constitution, utilizing action of the minor loop of the field cores of semi-hard magnetic material, the residual magnetic flux density of the plurality of field cores is controlled in sequence and the shifting magnetic field is induced thereby the magnetic poles of the rotor are attracted in sequence so as to move the rotor.

Abstract: An inductive pulse generator for converting a rotary movement into a frequency proportional therewith. The pulse generator includes a measuring wheel (1) provided with poles (3) of magnetic material evenly distributed over the circumference of the measuring wheel. The pulse generator further includes a stator (4) provided with a magnetic core (6) with plate-shaped pole shoes (10) in a coil carrier (8) out of which end portions (12) of the pole shoes (10) project. The end portions (12) face the measuring wheel (1). A coil (7) surrounds the magnet core (6), at which coil (7) a pulsating voltage can be picked off with a frequency proportional to the number of revolutions of the measuring wheel (1), outside the area of the pole shoe (10) end portions (12) facing the measuring wheel (1). The thickness of the pole shoes (10) is increased by additional magnetic material (11) so as to increase the pulsating voltage which can be picked off at the coil (7).

Abstract: A magnetic structure including a stator including sensor windings and a field exciter, and a movable armature having a variety of applications, including a synchro resolver and a tachometer. The stator comprises a plurality of planes of oppositely polarized parallel magnetic pole pieces contained in an annular or toroidal structure of rectangular cross-section to circumferentially surround the movable rotor or armature. The parallel pole pieces of opposite polarity form a segment extending radially inward, and are surrounded by a plurality of sense windings, wherein the rotor selectively provides a relatively low reluctance path to one or more of the pole pieces, causing a change in flux and corresponding voltage to be produced in the sense windings. In one embodiment, the pole pieces are energized by a permanent magnet located in the stator to produce a tachometer output voltage upon the sense windings. In that configuration the sense winding signals vary in amplitude according to velocity and position.

Abstract: A dual magnetic sensor utilizing a pair of separate coils to generate separate and isolated signals from a single pickup point, each signal having a power output at least equal to that of a conventional single coil sensor, the dual sensor having physical dimensions making it substitutable for a conventional single coil sensor.

Abstract: A variable magnetic reluctance generator is disclosed generally comprising a stator having pairs of spaced magnetic poles of opposite polarity. Like polarity poles are adjacent one another to define a gap having all poles of the same polarity on the same side, and permanent magnet means provide an essentially uniform magnetic field intensity along the length of the gap. The opposite polarity poles are connected by a magnetically permeable path that is surrounded by a stator winding. The rotor has alternating segments of high and low magnetic permeability and these segments move through the gap between the opposite polarity poles, which changes the magnetic permeability between them. This causes variations in the magnetic flux in the magnetically permeable path, which induces an electrical current in the surrounding stator winding. Output voltage may be controlled by auxiliary field coils on the stator or by other means.

Abstract: A stator adapted for mounting adjacent the periphery of a moving machine gear, whereby the gear serves as a rotor in an electric alternator. A pair of elongated pole pieces are mounted in parallel adjacent the gear periphery. Dependent teeth are formed on each of the ends of each pole piece. The ends of the teeth of the pole pieces are separated from the gear tooth tips by a short air gap. The pole pieces are of length such that when the teeth at one end of a pole piece overlie gear tooth tips, the teeth at the opposite end of that pole piece overlie spaces between gear teeth. The pole pieces are displaced longitudinally relative to one another so that when the teeth at one end of one pole piece overlie gear tooth tips, the teeth at the like end of the other pole piece overlie spaces between gear teeth. Magnets are positioned between the pole pieces, one at each end. Gear motion induces electrical potentials in conductor coils wound on the pole pieces.

Abstract: A device for detecting the speed of rotation and/or an angle of rotation of a shaft having a motion transmitter which rotates with the shaft, the device consisting of a magnetic-field-dependent sensor which receives a signal from the motion transmitter. A permanent magnet is arranged in the vicinity of the sensor with an evaluating circuit, the sensor being an integrating component of the evaluating circuit. The arrangement of the permanent magnet with respect to the sensor and of the permanent magnet and sensor with respect to the motion transmitter, on the one hand, and the construction of the sensor as a saturable-core probe (fluxgate effect), on the other hand, make it possible to detect even very slow rotational movements such as occur, for example, with antiblocking systems or forward drive control systems in motor vehicles.

Abstract: A rotation detector for detecting the rotational speed and phase of the upper rotary drum of a guide drum of a VTR in respect to the stationary drum of the guide drum as the upper rotary drum rotates about its rotational axis, the rotation detector including a magnet mounted on the lower surface of the upper rotary drum along a first circumferential path which is coaxial with the rotational axis of the upper rotary drum, five yoke members mounted along the first circumferential path on the lower surface of the upper rotary drum with the magnet and each yoke member being equally spaced from one another along the first circumferential path, a first iron core having a coil wound about it mounted on the stationary drum along a second circumferential path which is coaxial with and opposing the first circumferential path for producing a signal corresponding to the rotational phase of the upper rotary drum in response to the passing of only the magnet during rotation of the upper rotary drum, and two second iron cor

Abstract: An inductive transmitter has a housing 1 within which two pole shoes 8, a permanent magnet 7 arranged between the pole shoes 8 and a coil 6 surrounding the permanent magnet 7 and the pole shoes 8 are arranged. The two ends of the coil 6 are connected with an output connection from which a cable 16 is conducted outwardly from the housing 1. The electric components, such as the coil 6, output connection pieces 9, 9' and output connection contacts 23, 23', are arranged in the watertight inside of the housing 1, while the permanent magnet 7 and the pole shoes 8 are received in a pot-shaped recess 14 developed communicatingly outside the inside of the housing in a coil support.

Abstract: A unitized (single unit) motor and flux switch alternator having stationary field, armature and motor windings which provides a magnetic path for some of the motor input power to feed through and increase the alternating current (AC) generator output. A rotor formed from a material having a high magnetic permeability (solid or laminated soft steel) is controlled in speed by controlling the magnitude and timing of the pulsed direct current (DC) supplied to the motor windings which may be wound on the stationary legs or the rotor. The current flow in the motor windings can be controlled by a mechanical commutator if the motor windings are on the rotor or by a solid-state converter if the motor windings are on the legs in a manner normally associated with brushless DC motors. The DC windings of the flux switch alternator can be replaced by permanent magnets since the reversing field in the AC output windings are predominantly time stationary.

Abstract: In a signal generator with a magnetic rest, consisting of a ferromagnetic studded disk (13) with a U-shaped part (6) consisting of a permanent magnet (3) and lateral ferromagnetic small plates (4,5), two brackets (7, 8) are provided for on a support (1) between which the permanent magnet (3) and the small plates (4, 5) are capable of being clampingly inserted. This permits an easy assembly and adjustment of the permanent magnet (3) as well as of the small plates (4, 5).

Abstract: To increase the output amplitude obtained from Wiegand wire transducers, for example of the type used in contactless ignition breaker systems, a flux concentration or flux guide element (3) of highly permeable material, for example high-frequency ferrite core material, is provided surrounding the Wiegand wire (1) and, at least in part, the pick-up coil (2) coupled thereto.

Abstract: An electromagnetic transducer which generates signals on the basis of the Barkhausen effect under periodically alternating externally applied magnetic switching fields. Prior to use, the magnetic sensor element, for example a ferromagnetic wire, is pre-magnetized by undergoing a program which subjects the wire to a coercive applied field substantially higher than the alternating interrogation field. The coercive field places different zones of the wire into magnetic saturation with varying relative polarity, thereby creating two or more zones of different magnetization. When subjected to the alternating, low intensity interrogation field, sensor coils detect a high level, bipolar output signal.

Abstract: A frequency independent log periodic acoustic device is utilized for the transmission or reception of underwater sound. A key element of the device is a particularly shaped plate or diaphragm, called a filter plate, made of stainless steel or other material having suitable acoustic properties. The filter plate on being placed in front of any plane wave receiving or transmitting transducer acts automatically to make the beamwidth of the diffraction pattern of the combined device constant, regardless of frequency. This is achieved by automatically making the effective aperture diameter of the filter plate-transducer combination a constant multiple of the acoustic wavelength of the sound in the underwater medium. When used in conjunction with a scannable transducer such as an acoustic lens and the retina device the filter plate produces a directional, scannable, substantially constant beamwidth diffraction pattern for radiation or reception of underwater acoustic signals.

Abstract: Several embodiments of tachometers generators for use in controlling the speed of electrical motor driven tools. In each embodiment a toothed rotor (28, 52, 72, 92, 122) is fixed for rotation with the motor armature shaft (23, 53, 73, 93, 124) and a sensor (31, 55, 75, 96, 126) is juxtaposed to the rotor. The sensor is comprised of a core (32, 56, 76, 98, 127) having a first end portion (33, 57, 77, 99, 128) juxtaposed at a first location relative to the rotor and a second end portion (36, 58, 78, 101, 129) that is juxtaposed to the rotor at a second, spaced location. A permanent magnet (37, 59, 79, 102, 131) is interposed between the second end portion and the rotor with one of its poles aligned with a second end portion and the other of its poles aligned with the rotor.

Abstract: A reluctance machine comprises a rotor having a plurality of unwound salient rotor poles, and a stator with an even number of mutually equal groups of salient stator poles evenly distributed around the inner circumference of the stator unit, each stator pole being surrounded by a respective working coil. The stator poles belonging to the same group have the same polarity and also the same premagnetization. The polarity is determined by the working coils being distributed between at least two working windings which are each provided with a rectifying means. Between two stator poles, whose working coils belong to one and the same working winding, there is at least one stator pole which supports a working coil belonging to some other working winding.

Abstract: A pulse generator composed of a stator, a part which is movable with respect to the stator, a coil of wire, at least one Wiegand wire, and at least one magnet which causes the Wiegand wire to generate pulses in the coil based on the Wiegand effect, upon movement of the movable part. The magnetic field produced by the magnet is of such an asymmetrical form with respect to the Wiegand wire that the pulses show a positive or negative polarity depending on the sense of movement of the movable part.

Abstract: A signal generating device comprising a bistable magnetic device which alters its magnetic state when the density of magnetic flux to which it is subject passes through a predetermined value, and detecting means providing an output signal responsive to a change in magnetic state of said bistable device. A conducting means for magnetic flux comprises a first portion providing a first path of high permeability and a second portion, and has the bistable device connected between the first and second portions for conducting therebetween and being subjected to the conducted magnetic flux. The second portion provides second and third paths through the bistable device, each having a respectively alterable permeance for varying in an opposite relationship the respective reluctance of the second and third paths of the conducting means and the density and sense of magnetic flux to which the bistable device is subject.

Abstract: A multiple coil electromagnetic pickup converts into signals the flux varions produced by the passing of the teeth of a sound wheel. The pickup comprises at least two assemblies each consisting of at least one coil, one pole piece and one straight magnet all axially aligned, the assemblies being arranged in parallel to each other and magnetically insulated from each other by a screen. Measurement of rotational speed produces two output signals.

Abstract: A magnetic probe for sensing the passage of a moving magnetic element, comprising a radially magnetized cylindrical permanent magnet, formed of a flat sheet of elastomer bonded ferrite material magnetized across its smallest dimension and curled to cylindrical configuration, or formed in cup-shaped configuration. A magnetic collector core is mounted co-axially in one end of the magnet cylinder and has an axial pole piece of reduced diameter projecting to the other end of the magnet cylinder, and an electrical sensor coil encompasses the pole piece; the sub-assembly comprising the magnet, the core, and the coil is mounted in a cylindrical magnetic housing, with only high-reluctance flux paths between the inner surface of the permanent magnet and the housing.

Abstract: A signal generating means comprising a bistable magnetic device which alters its magnetic state when the density of magnetic flux to which it is subject passes through a predetermined value, and detecting means providing an output signal responsive to a change in magnetic state of said bistable device. A conducting means comprising first and second portions conducts magnetic flux in first and second paths and subjects the bistable magnetic device which is connected between the first and second portions to the conducted magnetic flux. The second portion provides the second path with an alterable permeance for varying the reluctance of the second path of the conducting means, and an energizing means provides magnetic flux to the conducting means having a sense along the first path through the bistable device which is opposite to its sense in the second path.

Abstract: An improved magnetic sensor assembly comprising a permanent magnet recessed within a pole extension magnet with a pick-up coil disposed around a portion of the pole extension magnet, each of the permanent and pole extension magnets having one end thereof substantially coplanar. The sensor assembly may be enclosed within a magnetic shield having an access opening providing access to the sensing region of the sensor assembly.

Abstract: Magnetic pickup having a matrix-bonded permanent magnet sleeve around one end of an elongated cylindrical pole piece and a coil around the other end. The magnet sleeve has a preferred direction of magnetization radial to the axis of the pole piece.

Abstract: An apparatus for detecting the presence and/or direction and/or velocity of a moving ferromagnetic element is provided. A sensing coil is placed in coupling relationship with a bi-stable ferromagnetic wire to provide a signal in response to a change in polarity of the core of the bi-stable wire. The core polarity changes in response to element presence as the element constitutes a magnetic shunt causing a change in magnetic flux density and/or direction in the air gap of a magnetic circuit in which the bi-stable wire is situated. The sensor is substantially insensitive to element velocity. Modified structures provide for fail-safe operation.

Abstract: A Wiegand wire is placed within the magnetic field generated by a first and second permanent magnet. The first permanent magnet has a field strength exceeding that of the second permanent magnet and the polarity of its magnetic field is opposite that of the second magnet. A rotor having segments of magnetic shielding alternating with slots is rotated between the Wiegand wire and the first magnet. When the magnetic shielding is between the first magnet and the Wiegand wire, the latter is exposed only to the magnetic field of the second permanent magnet. In a second position of the rotor, the Wiegand wire is exposed to both magnetic fields. Since the second permanent magnet generates a stronger field than the first, the direction of magnetization in the Wiegand wire changes abruptly causing a pulse to be generated in pick-up coil 4.

Abstract: A speed sensor for a vehicle wheel has a rotating tone wheel with a stationary magnetic sensor having a pair of sensing poles positioned proximate the tone wheel teeth. Coil means are wound on the poles and the poles are magnetized to induce a signal voltage in the coil means corresponding to wheel speed. The poles are phased relative to the teeth on the tone wheel to reduce noise voltage components in the wheel speed signal voltage due to axial misalignment and vibration of the tone wheel. The poles may be phased 180.degree. relative to one another with respect to the teeth on the tone wheel so that one pole is in registry with a tooth when the other pole is in registry with a space between two teeth. With this arrangement the combined reluctance of the poles is approximately constant.

Abstract: A magnetic probe for sensing the passage of a moving magnetic element, comprising a radially magnetized cylindrical permanent magnet, formed of a flat sheet of elastomer bonded ferrite material magnetized across its smallest dimension and curled to cylindrical configuration, or formed in cup-shaped configuration. A magnetic collector core is mounted co-axially in one end of the magnet cylinder and has an axial pole piece of reduced diameter projecting to the other end of the magnet cylinder, and an electrical sensor coil encompasses the pole piece; the sub-assembly comprising the magnet, the core, and the coil is mounted in a cylindrical magnetic housing, with only high-reluctance flux paths between the inner surface of the permanent magnet and the housing.