Abstract: A testing apparatus for use with a data storage component that includes a base platform and a retaining element coupled to the base platform. The retaining element is sized and configured to retain the data storage component. The retaining element is linearly movable relative to the base platform during a linear acceleration mode without substantial rotational movement. The retaining element is rotationally movable relative to the base platform without substantial linear movement during a rotational acceleration mode. The testing apparatus further includes an actuator disposable in mechanical communication with the retaining element for moving the retaining element relative to the base platform.

Abstract: A device and system are provided for monitoring acoustic emissions from machinery to indicate levels of detected sound waves. Each incorporates an acoustic sensing device which incorporates a housing assembly constructed for removable attachment between a surface mounting region of the machinery and a measuring instrument to define a coupled state. An acoustic emissions sensor is disposed in the housing assembly's interior to detect sound waves propagating through the surface mounting region and to produce detection signals for processing by the measuring instrument. A methodology for monitoring acoustic emissions is also provided.

Abstract: An additional mass member 22 for measuring resonance of a bearing device comprises an elastic ring 30 having an inner periphery 30a larger in diameter than the outer periphery of the outer ring 24 of the bearing device 25 and being contracted and expanded in the radial direction, and a fixed ring 31 having a large rigidity and fitted onto the elastic ring 30. The elastic ring 30 is fitted to the outer ring 20, and then the fixed ring 31 is fitted to the elastic ring 30 to push the elastic ring 30 in the radial direction, so as to contract the inner periphery 30a of the elastic ring 30, so that the additional mass member 22 is fixed to the bearing device 21, whereby the resonance frequency of the bearing device having a double row of bearings can be measured precisely and readily.

Abstract: An output signal that accords with a rotation speed of a brake rotor of a respective wheel is output by a vehicle wheel speed sensor. A noise frequency identification portion identifies a frequency component that corresponds to brake noise from this output signal. It is possible, for example, to identify a frequency component that corresponds to brake squeal by performing fast Fourier transform (FFT) calculation for the vehicle wheel speed. Further, a noise detection portion determines that brake noise is being generated when the frequency component identified by the noise frequency identification portion is equal to or more than a predetermined value.

Abstract: In the method of detecting a localized sun gear fault, in the operation of an epicyclic gear train having ring, planet and sun gears, and a planet carrier, the steps that include detecting sun gear vibrations transmitted through each planet gear, computing separated averages of such detected vibrations, phase shifting the averages to account for the differences in gear meshing positions, and re-combining the phase shifted averages to produce a modified average value of the sun gear vibration.

Abstract: A system and method for testing at least one joint in a linkage includes a platform system, a torque system, an articulation assembly and a fault detection system. The platform system receives a first shaft connected to a first joint in the linkage and the torque system applies torque to the first joint without substantially rotating the first shaft or joint, a second shaft connected to a second joint in the linkage or the second joint. The articulation assembly receives the second shaft and moves the second joint in a substantially circular path without substantially rotating the first shaft or joint and the second shaft or joint. The fault detection system determines the condition of the linkage based upon detected signals emitted from the linkage while the first joint is torqued and the second joint is moved.

Abstract: A wheel rotation detecting device including a sensor unit that is supported on a stationary ring which does not rotate even when the wheel is in use, and the rotation of the wheel that is attached to a rotary ring can be detected by a rotation detecting sensor held within the sensor unit. Within the sensor unit, in addition to a rotation detecting sensor, there are disposed other sensors such as a temperature sensor and a vibration sensor, thereby allowing detection of the rotation speed and the rotation number of the wheel supported on the rotary ring, as well as detection of other car driving conditions.

Abstract: A system for monitoring mechanical waves from a machine which in operation has moving particulate matter therein, the system including at least one sensor located on the machine at a location away from the central axis of the machine, the sensors being for sensing acoustic waves and including a transmitter for transmitting signals representing the sensed mechanical waves to a receiver at a location remote from the sensor(s), a data processor connected to the receiver for receiving signals from the receiver which signals represent the mechanical waves and processing the signals to produce output signals for display on a display means, wherein the output signals for display represent one or more parameters indicative of mechanical waves emitted from the machine over a predetermined period of time.

Abstract: Sensor assembly for measuring a load on a bearing having at least one bearing ring (11), the at least one bearing being provided with a cavity (12) for holding the sensor assembly. The sensor assembly comprises a series mounting between opposing sides (17, 18) of the cavity (12), the series mounting comprising a piezoelectric plate (16) and a spring (19) with spring stiffness k. Alternatively, the sensor assembly further comprises a body (14) with mass in mounted between the piezoelectric plate (16) and the spring (13), to allow simultaneous load measurement and health monitoring.

Abstract: A data collector having an integrated laser tachometer. The data collector includes, within a housing that can be held by a single hand, circuitry for receiving a vibration signal to be digitized, as well as an optical system for receiving light from outside said housing to be converted to a digital tachometer signal. Digital signal processing circuits within the housing receive, store or process the digitized vibration signal and/or the digital tachometer signal, for the purpose of predictive maintenance. The housing of the data collector also holds a display and input keys, so that an operator may use the same hand for holding and controlling the data collector, and for holding the integrated laser tachometer. This frees a hand for holding an accelerometer or for other purposes. Use of a data collector with an integrated laser tachometer is thus substantially more convenient than using a data collector with a separate, nonintegrated laser tachometer attachment.

Abstract: An online bearing monitor is provided that is threaded to the lubrication port of a bearing of a machine. The online bearing monitor of the present invention contains a temperature and vibration sensor, a lubrication level sensor optionally detachably coupled to the lubrication device, on board intelligence, and both wire and wireless electronics. The monitor provides for two-way communication to detect the lubrication and maintenance needs of a machine bearing. The monitor processes and stores temperature and vibration signals on site to determine corrective measures. The corrective measures can be conveyed wire or wirelessly to remote stations.

Abstract: In the method of detecting a sun gear fault, in the operation of an epicyclic gear train having ring, planet and sun gears, and a planet carrier, the steps that include detecting sun gear vibrations transmitted through each planet gear, computing separated averages of such detected vibrations, phase shifting said averages to account for the differences in gear meshing positions, and re-combining said phase shifted averages to produce a modified average value of the sun gear vibration.

Abstract: The present invention is for a system (11) or method for conditioned based monitoring of a bearing assembly. The system (11) comprises a sensor (13) placed in proximity to a bearing assembly (12). The sensor (13) generates a signal indicative of the amplitude and frequency of the vibrational movement of the bearing assembly. A process (14) in communication with the sensor (13) receives the signal from the sensor (13) and generates spectral data representative of the bearing vibrational movement. A database (15) comprises data representative of an amplitude threshold, for at least one predetermined frequency, characteristic of a bearing fault. The processor (15) compares the spectral data to the amplitude threshold and generates a signal indication of the bearing assembly.

Abstract: An output signal that accords with a rotation speed of a brake rotor of a respective wheel is output by a vehicle wheel speed sensor. A noise frequency identification portion identifies a frequency component that corresponds to brake noise from this output signal. It is possible, for example, to identify a frequency component that corresponds to brake squeal by performing fast Fourier transform (FFT) calculation for the vehicle wheel speed. Further, a noise detection portion determines that brake noise is being generated when the frequency component identified by the noise frequency identification portion is equal to or more than a predetermined value.

Abstract: A method for compensating for a mechanical oscillation which has a frequency spectrum which can be approximately represented by a number of discrete frequency components, at a machine shaft via at least one actuator acting directly or indirectly upon the machine shaft. At least upon one of the discrete frequency components of the mechanical oscillation is superposed by the actuator, independently of the other frequency components, at least one substantially harmonic torque of the same frequency having a specific amplitude and phase in such a manner that the amplitude of the oscillation of the machine shaft at the this frequency is reduced.

Abstract: An additional mass member 22 for measuring resonance of a bearing device comprises an elastic ring 30 having an inner periphery 30a larger in diameter than the outer periphery of the outer ring 24 of the bearing device 25 and being contracted and expanded in the radial direction, and a fixed ring 31 having a large rigidity and fitted onto the elastic ring 30. The elastic ring 30 is fitted to the outer ring 20, and then the fixed ring 31 is fitted to the elastic ring 30 to push the elastic ring 30 in the radial direction, so as to contract the inner periphery 30a of the elastic ring 30, so that the additional mass member 22 is fixed to the bearing device 21, whereby the resonance frequency of the bearing device having a double row of bearings can be measured precisely and readily.

Abstract: In a movable space, a boundary (CN1) between a ceiling surface and a wall surface of a cap (CA) has a curved plane. When stress is exerted on the cap (CA), this stress is dispersed accordingly around the boundary (CN1) having a high probability of generation of a crack. Therefore, generation of a crack in the cap (CN) is unlikely.

Abstract: Sensor assembly for measuring a load on a bearing having at least one bearing ring (11), the at least one bearing being provided with a cavity (12) for holding the sensor assembly. The sensor assembly comprises a series mounting between opposing sides (17, 18) of the cavity (12), the series mounting comprising a piezoelectric plate (16) and a spring (13) with spring stiffness. Alternatively, the sensor assembly further comprises a body (14) with mass in mounted between the piezoelectric plate (16 ) and the spring (13), to allow simultaneous load measurement and health monitoring.

Abstract: The present invention discloses a system for non-contact measurement of vibrational motion in a vibratory compacting machine. The system includes a vibrating element such as a roller drum adapted for vibrational motion and a non-contact sensor positioned a distance from the vibrating element and adapted for sensing the vibrational motion of the vibrating element. The present invention also discloses a method for non-contact measurement of vibrational motion of a vibrating element in a vibrating element that includes sensing position information of the roller drum with a non-contact sensor positioned a distance from the vibrating element and determining at least one vibration characteristic based on the position information sensed with the non-contact sensor.

Abstract: A diagnostic vibration analyzing system and method for measuring and characterizing the torsional vibrations in a vehicle or a piece of industrial equipment (collectively a “vehicle”). An electronic control unit and sensor cooperate to measure speed fluctuations occurring between the passing of adjacent teeth of a rotating gear. These time measurements are the basis for displacement, velocity and acceleration calculations which, combined with driveshaft rotational order information, can be used to pinpoint the source of excessive driveline torsional vibrations. The use of multiple sensors can maximize per test the information available for analysis. The use of multiple sensors in a substantially simultaneous manner can isolate particular components in the tested vehicle.

Abstract: A surface to serve as a surface under ultrasonic inspection has a roughness of 0.4 &mgr;mRa or less, and wherein all imperfections existing a controlled volume X corresponding to all cross sections of a raceway ring 1 assume a length of 0.2 mm or less as represented by the square root of areas of the imperfections. Accordingly, it is possible to provide a rolling bearing which does not become short-lived and obviates a concern about occurrence of cracking even when used in a harsh environment.

Abstract: The invention relates to a method for evaluating the condition of a machine (100) with a measuring point (90), which method is performed by a movable analysis apparatus (30). The method comprises the steps of producing a condition value, by means of measuring at the measuring point, which condition value is dependent on the actual condition of the machine, and storing the condition value in a writable information carrier (120) which is placed by, or in the vicinity of, the measuring point (90) so that the condition value subsequently can be used as a reference condition value. The invention further relates to an apparatus for performing the method and a device for cooperating with the analysis apparatus and for mounting by a measuring point on the machine (100).

Abstract: The present invention provides a method for signal vibration alert. The method of the present invention recognizes significant substantial swerves and corresponding substantial edge-to-edge differences by eliminating the adverse effect of noise among signals generated by an apparatus. When the frequency of the substantial edge-to-edge differences that exceed an acceptable range of the frequency limit is too large, the method of the present invention automatically generates an alert to indicate aberration in the apparatus such that the monitoring staff is informed and allowed to take necessary measures responding to the aberration.

Abstract: A bearing monitor has a bearing sensor to monitor frequencies emitted by a bearing in a rotating component. The bearing sensor has an output to a processor. The processor is attached to the rotating component to process the output from the bearing sensor to a digital or logical signal, which may include determining if the output indicates that the bearing requires service.

Abstract: A device and system are provided for monitoring acoustic emissions from machinery to indicate levels of detected sound waves. Each incorporates an acoustic sensing device which broadly comprises a housing assembly constructed for removable attachment between a surface mounting region of the machinery and a measuring instrument to define a coupled state. An acoustic emissions sensor is disposed in the housing assembly's interior to detect sound waves propagating through the surface mounting region and to produce detection signals for processing by the measuring instrument. A methodology for monitoring acoustic emissions is also provided.

Abstract: The processing method, starting from the measurements of the vibration of a bearing block (5) or a rotor (2) of a rotating machine (3) consists particularly of: starting from spectral decompositions [Ax(fi), &PHgr;x(fi)] and [Ay(fi), &PHgr;y(fi)], calculating a spectral decomposition in elementary elliptical trajectories of the displacement of the rotor axis, defined by a series of sets of at least three data [Emax(fi), Emin(fi), E&phgr;(fi)] where: Emax(fi) is the maximum radius of the elementary ellipse at frequency fi, Emin(fi) is the minimum radius of the elementary ellipse at frequency fi, E&phgr;(fi) corresponds to the value of the orientation angle of the principal axis of the elementary ellipse, and may be positive or negative depending on the direction of movement around the ellipse. Save the series [Emax(fi), Emin(fi), E&phgr;(fi)].

Abstract: The x- and y-direction vibration components of radial vibration of a rotational shaft 106 obtained by measurement from x and y directions are transformed into frequency sample values {XkYk, k=0, 1, . . . N−1} by discrete Fourier transform. RMS amplitude values {2½|Fki(2j&pgr;/M)|, j=0, 1, . . . M/2−1} are calculated at azimuths {&thgr;j=2j&pgr;/M, j=0, 1, . . . M/2−1} corresponding to 0 to &pgr; on the basis of frequency sample values at frequency points {ki, i=1, . . . P} corresponding to specific frequencies {fi, i=1, . . . P} of NRRO vibration components selected from the x- and y-direction frequency sample values obtained by the discrete Fourier-transform. RMS evaluation values Aki are selected from these RMS amplitude values.

Abstract: A system for monitoring the structural condition of a helicopter rotor assembly component includes a piezoelectric sensor. Acoustic emission signal techniques allow for recognizing the relatively high frequency stress waves associated with the propagation of cracks or defects in a rotor assembly component. A signal conditioner processes the sensor signal and provides an output signal that includes at least one characteristic that is indicative of the content of the sensor signal and, therefore, the structural condition of the item of interest. A signal analyzer utilizes the output signal from the signal processor to determine the structural condition of the component.

Abstract: A method is provided of identifying a rotating bearing defect featuring the steps of measuring the vibration of the rotating bearing to obtain a waveform signal; filtering the waveform signal to remove unwanted signal frequencies; enveloping the filtered waveform signal to obtain an enveloped low frequency time waveform; and synchronizing the enveloped low frequency time waveform to the running speed of the rotating bearing in such a way to preserve the phase relationship between the tachometer pulse and bearing defect to obtain a time synchronized waveform. The method may include the step of measuring the rotational speed of the rotating bearing; and the step of measuring the rotational speed of the rotating bearing comprises measuring the rotational speed of the rotating bearing with a tachometer.

Abstract: Stationary sensors are used to measure periodically the vibratory motions of portions of a body spinning in front of them, such as blades, and to try to determine their natural frequencies by spectral analyses. The sensors are collected together in several networks of different numbers and the determination includes a comparison of the spectra of the different networks via different operations of selection and rejection of lines. The process appreciably pushes back the limit of unambiguous frequency detection.

Abstract: A foreign object impact sensor for use with combustion turbines utilizes a passive acoustic waveguide within the turbine to receive acoustic signals from foreign object impact. The magnitude of these signals is displayed and or stored using a lighted display or other suitable indicating device. The information is also recorded and stored, so that a spectrum signature can be obtained from Fourier analysis.

Abstract: A noise reduction system reduces noise associated with an input signal provided to a control system, while substantially minimizing the adverse affect on the responsiveness and stability of the control system. The noise reduction system includes a processor, a memory subsystem and processor executable code. The processor executable code causes the processor to perform a number of steps. Initially, the processor determines an input signal level of an input signal at an input of a noise reduction system. Next, the processor determines an output signal level of an output signal at an output of the noise reduction system. The processor then determines a magnitude of a difference signal which is the difference between the input signal level and the output signal level. When the magnitude of the difference signal is less than a predetermined noise limit, the input signal is provided to an input of a control system.

Abstract: Detecting blade vibration via ultrasonic waves is disclosed. The blade may be part of a robot that is used in conjunction with semiconductor device fabrication. A process chamber is provided that has a sidewall and a base defining a cavity contained therein. A rotatable blade is mounted at a center of the cavity that has a base portion and a tip portion extensible from the center to the sidewall of the process chamber. One or more ultrasonic sensors are mounted on the base adjacent to the sidewall. Ultrasonic waves are sent and received toward and reflected by the tip portion of the wafer blade to determine the tip portion's position. In this way, vibrational movement of the blade can be detected.

Abstract: A fault detection system for determining whether a fault exists with a rotating element of a vehicle. The system includes a transducer, a diagnosis sampler, and a controller. The transducer may be a microphone located in the vehicle for converting sounds to an electrical signal. The electrical signal includes a noise component generated from the rotating element. The diagnosis sampler is connected to the transducer and provides a sample of the electrical signal from the transducer to the controller. The controller has functional aspects such as an envelope detect, a spectrum analysis, and a fault detect. The envelope detect has the capability of detecting an envelope of the electrical signal. The spectrum analysis has the capability of forming a spectra from the envelope of the electrical signal, where the spectra is associated with the noise component generated from the rotating element.

Abstract: The processing method, starting from the measurements of the vibration of a bearing block (5) or a rotor (2) of a rotating machine (3) consists particularly of:

Abstract: To enhance a detecting capability for monitoring a bearing assembly and also to minimize complication of the structure resulting from increase in functionality, a vehicle mounted bearing assembly 51 includes inner and outer members 2 and 1 with rows of rolling elements 3 operatively interposed between the inner and outer members 2 and 1, and a rotation detecting sensor 4. A sensor output from the rotation detecting sensor 4 is digitalized by a digitalizing unit 101 and is subsequently transmitted wireless by a transmitting unit 105. One or both of status detecting sensors 52, 53 for detecting different statuses of the bearing assembly 51 other than rotation such as temperature and vibration occurring in the bearing assembly 51 may be additionally employed. A signal coordinating unit 104 may also be used for coordinating the respective sensor outputs from the rotation detecting sensor and the status detecting sensors to enable those sensor outputs to be transmitted wireless by the transmitting unit 105.

Abstract: A method of identifying a rotating bearing defect comprising the includes of: measuring the vibration of the rotating bearing to obtain a waveform signal; filtering the waveform signal to remove unwanted signal frequencies; enveloping the filtered waveform signal to obtain an enveloped low frequency time waveform; and synchronizing the enveloped low frequency time waveform to the running speed of the rotating bearing to obtain a time synchronized waveform.

Abstract: An acoustic signal unit comprises a signal generation unit to generate a first electrical signal, a first transducer to generate an acoustic signal in response to the first electrical signal, and a second transducer to generate a second electrical signal in response to the received acoustic signal. A calculation unit is provided to compare the first and second electrical signals to determine the time of flight of the acoustic signal, wherein the time of flight corresponds to the stress in the rolling element bearing. The stress may be calculated according to a formula or by multiplying an acoustic time constant for the rolling element bearing by the distance traveled by the acoustic signal across the rolling element bearing, and by the time of flight determined by said comparison unit.

Abstract: An externally-powerable sensor is described for detecting ultrasonic energy and for providing an accurate indication of the level of such energy to an external monitoring device over a wide dynamic range. A first electrical signal proportional to the detected ultrasonic energy is chopped by the output of a free-running multivibrator to generate a signal having a frequency differing from the frequency of the first signal by an amount within the audio frequency range. Such difference signal is selectively amplified to concentrate the spectral energy of the difference component in a lower portion of the audio range. A low pass filter extracts, from the so-concentrated difference signal, a modified audio signal whose frequency content is at the lower end, illustratively 0-6 KHz, of the spectrum of the concentrated difference signal. The output of the low pass filter is processed to generate a DC output current that is proportional to the detected ultrasonic energy level.

Abstract: There is disclosed a sliding rotation member which is rotatably supported by a support shaft in a toroidal continuously variable transmission, and slides on another member, wherein a maximum shear stress depth generated at a maximum deceleration time of the toroidal continuously variable transmission is defined as Z0, a size of a defect obtained in accordance with a shape of the defect detected by a nondestructive inspection method is defined as a square root length, and then a defect of 0.05 mm or more in terms of the square root length is not included in a range of a depth from the surface which is twice the depth Z0.

Abstract: A method of verifying spindle bearing functionality prior to service, comprising: assembling a machine-tool spindle having an outer housing rotatably supporting an inner spindle shaft about a spindle axis by use of roller bearing sets, at least one set being compressed along the spindle axis to promote a resilient bearing preload force between the housing and shaft; suspending the housing of said assembly on a non-resonating flexible support, the spindle shaft being essentially isolated from the housing except for the preloaded rolling bearing set; sharply striking the inner spindle shaft along said spindle axis to induce an axially oscillating frequency; measuring the oscillating frequency in the shaft as it is affected by the degree of bearing preload of such at least one bearing set; and comparing the measured induced frequency to a known frequency analysis for the type of spindle assembly which is correlated to varying bearing preloads, the comparison indicating the spindle bearing functionality prior to

Abstract: A method and system for monitoring the condition of a bearing mounted on a rotating shaft, particularly one present in an aircraft gas turbine engine, where the vibration sensor that monitors the bearing is remote therefrom but proximate to the rotating shaft. The vibration sensor obtains a broadband signal having frequencies that include the bearing defect peak of the monitored bearing. The broadband signal is analyzed to identify the presence of the bearing defect peak. If the bearing defect peak is present, the amplitude of this peak is quantified to determine whether degradation of the monitored bearing has at least reached a threshold criteria previously established.

Abstract: An apparatus for monitoring the health of a compressor comprising at least one sensor operatively coupled to the compressor for monitoring at least one compressor parameter, a calibration system coupled to the at least one sensor, the calibration system performing time-series analysis on the monitored parameter, a processor system for processing and computing stall precursors from the time-series analyzed data, a comparator that compares the stall precursors with predetermined baseline data, and a controller operatively coupled to the comparator which initiates corrective actions to prevent a compressor surge and stall if the stall precursors deviate from the baseline data which represents predetermined level of compressor operability. The processor system preferably includes a frequency demodulator and a system for processing the frequency demodulated signals to extract stall precursor characteristics.

Abstract: A method and a device for monitoring a bearing arrangement, having at least one bearing, in a mounting element of a roller journal bearing of a roller in a stand of a rolling mill train are designed to initiate upkeep or repair work on the bearing arrangement at the correct time. The method involves measuring a process quantity at the bearing or in an area adjoining the bearing, providing an evaluation device with the measured value of the process quantity, comparing the measured value with a stored preset value, and triggering a signal as soon as the measured value exceeds or falls below the stored preset value.

Abstract: A process and apparatus for determining the damage on at least one cyclically moving machine component, whereby a signal caused by the motion of the component is picked up by a sensor. At least one portion of the signal with an adjustable period is separated, and the remaining or separated part of the signal is subjected to damage analysis. In addition, a process and apparatus for separating periodic signal portions from a signal is provided, whereby the signal is supplied as an input signal to a rotating ring storage which is formed by cyclically arranged storage elements which are supplied in succession with the input signal currently at the input of the ring storage. A rotation frequency is synchronized with the period duration of the desired signal portions, and the desired signal portions are obtained as the output signal of the ring storage.

Abstract: A method and system for detecting drive train vibration. The system includes a programmable controller programmed to generate an output signal based on information from a wheel sensor located to sense the rotational behavior of an individual wheel. The controller is programmed to conduct a period test and a pattern test. A vibration of the drive train is detected in the event that both the period test and the pattern test are satisfied.

Abstract: A method and device for monitoring a bearing arrangement, having at least one bearing, in a housing of a roller journal bearing of a roller in a continuous casting installation are designed to initiate upkeep or repair work on the bearing arrangement at the correct time. The method involves measuring a value of a process quantity at the bearing or in an area adjoining the bearing, providing an evaluation device with the measured value of the process quantity, comparing the measured value with a stored preset value, and triggering a signal as soon as the measured value exceeds or falls below the stored preset value.

Abstract: The invention relates to a method for evaluating the condition of a machine (100) with a measuring point (90), which method is performed by a movable analysis apparatus (30). The method comprises the steps of producing a condition value, by means of measuring at the measuring point, which condition value is dependent on the actual condition of the machine, and storing the condition value in a writable information carrier (120) which is place by, or in the vicinity of, the measuring point (90) so that the condition value subsequently can be used as a reference condition value. The invention further relates to an apparatus for performing the method and a device for co-operating with the analysis apparatus and for mounting by a measuring point on machine (100).

Abstract: A Foreign Object Damage (FOD) detection system is disclosed for detecting and analyzing ultrasound or stress waves emitted when an object enters the intake of a turbine engine and impacts one or more of the blades in the engine. Upon detection the FOD detection system can immediately inform the operator, inform another electronic device (computer, etc.) and/or latch the event for review by maintenance personnel. The detection system generally consists of one or more stress wave sensors and an electronic assembly to process the stress wave signal received from the sensor(s). The electronic assembly is in communication with the sensor(s) via conventional cabling.

Abstract: An improved method, for obtaining a datum concerning the rotation speed (n) of a rotating object, such as a motor rotor (32), offers high precision. Typically, the motor has a sensor (61) which supplies a sensor signal that has, for each revolution of the rotor, a plurality A of events such as pulses or pulse edges which are counted by a microprocessor (23) associated with the motor. In order to keep the computation load on the microprocessor from increasing as the rotor speed increases, yet maintain high precision, the measurement is done over a full rotation of the rotor, starts at a first signal event (176), and ends after a third or nth signal event (182) which happens at the same rotational position as the first signal event.