A method for measuring a coil property, modeled as a parallel-circuit including a capacitance with a series-circuit including a DC-voltage and frequency-dependent resistance, and an inductance and current-voltage converter series connected, by: applying an AC-voltage, having a first-frequency and a DC-voltage component, to the coil and a voltage at the current-voltage converter is captured at a second-frequency, and the impedance and phase-angle at the first-frequency are derived from n-measured values; and applying an AC-voltage, having a third-frequency differing from the first and having a DC-voltage component, to the coil and voltage at the current-voltage converter is captured at the second or fourth-frequencies, in which the impedance and phase-angle at the third-frequency are derived from m-measured values for the DC-voltage resistance.

A sensor includes a ferromagnetic shield, at least one sensor coil disposed around an exterior of the ferromagnetic shield, and an electronics module within the ferromagnetic shield. The electronics module is configured to determine the position and/or orientation of the sensor based at least in part on a measurement of a signal induced in the at least one sensor coil.

A position sensor for sensing position or motion, includes: a ferrite core, and a sensor coil configured to provide a sensor signal. The sensor coil is implemented on a printed circuit board, and the ferrite core is configured to be fitted into the printed circuit board.

The sensor unit for a sensor/transmitter system is used to capture at least rotational and linear movements of a component (1) having magnetic poles. The sensor unit has at least one sensor which is at least one electrically conductive conductor bar (5) which is transverse with respect to the direction of movement of a magnetic field of the component (1). The relative movement between the magnetic field and the conductor bar (5) produces a voltage at said conductor bar, which voltage can be supplied to evaluation electronics (4).

A method and apparatus for detecting the displacement amplitude of an armature of a linear motor or alternator that is drivingly coupled to a load or prime mover. The method and apparatus require only three inputs all derived from the input terminals of the linear motor or alternator: (1) the voltage measured across the linear motor terminals; (2) the current consumed by the linear motor; and (3) the phase between the voltage and current. The three inputs are sensed at the terminals of the linear motor or alternator and used to perform mathematical calculations in the microcomputer of a control system or controller. The mathematical calculations are based on equivalent circuits that are modifications of the equivalent circuit for the linear motor or alternator. The detected displacement amplitude can be used by a controller to limit the displacement amplitude of the armature to prevent collisions.

A position sensor used in medical devices for use with medical positioning systems. The position sensor includes a core (80) having a body and one or more projections (841,842) extending from the body, wherein the core comprises a high-permeability material. The position sensor further includes a coil (74) surrounding the body, wherein the coil is configured to generate a voltage when subject to a magnetic field. The one or more projections extending from the body of the core are configured to concentrate the magnetic field into the coil and increase the voltage. Thus, various core designs are described which have projections which may increase the electrical and/or mechanical integrity of the position sensor and/or which may also induce magnetic flux flow within the position sensor thereby increasing the signals generated by the position sensor.

A system comprising: one or more field generating coils configured to generate a magnetic field; a sensor comprising a shell that contains a ferrofluid, the sensor configured to be introduced in proximity to the magnetic field, wherein the ferrofluid causes distortion of the magnetic field when the ferrofluid is in proximity to the magnetic field; and one or more field measuring coils configured to: measure a characteristic of the magnetic field when the ferrofluid is in proximity to the magnetic field; and provide, to a computing device, a signal representative of the measured characteristic of the magnetic field, wherein the computing device is configured to determine one or both of a position and an orientation of the sensor based on the measured characteristic of the magnetic field.

A resolver decoder circuit includes: a first filter circuit configured to calculate a first weighted sum of a first digital signal over a pre-determined period of time, where the first digital signal includes first digital samples of a first analog signal from a sine winding of a resolver; a second filter circuit configured to calculate a second weighted sum of a second digital signal over the pre-determined period of time, where the second digital signal includes second digital samples of a second analog signal from a cosine winding of the resolver, where the first and the second analog signals are configured to be induced by a sine signal applied to an input winding of the resolver; and a rectifier configured to generate a first output and a second output by adjusting a first sign of the first weighted sum and adjusting a second sign of the second weighted sum, respectively.

A feedback device for use in a gas turbine engine, and methods and systems for controlling a pitch for an aircraft-bladed rotor, are provided. The feedback device is composed of a circular disk and a plurality of position markers. The circular disk is coupled to rotate with a rotor of the gas turbine engine, to move along a longitudinal axis of the rotor, and has first and second opposing faces defining a root surface that extends between and circumscribes the first and second faces. The plurality of position markers extend radially from the root surface, are circumferentially spaced around the circular disk, and extending along the longitudinal axis from a first end portion to a second end portion. At least part of the first end portion and/or of the second end portion comprises a material having higher magnetic permeability than that of a remainder of the position markers.

A shaft monitoring system includes a rotatable shaft having a target element coupled thereto that rotates along with the shaft. A proximity sensor is located adjacent to the target element. The proximity sensor measures an inductance of the target element based on one or both of a volume of the target element and a distance between the target element and the proximity sensor, and generates a proximity sensor output signal based on the measured inductance. A signal processing system determines at least one of a position of the shaft, a rotational speed of the shaft, and a rotational direction of the shaft based on the proximity sensor output signal.