Abstract: The behavior of the bogie of a muliple-axle vehicle is monitored. Accelerations of at least two axles of the bogie are measured with acceleration sensors allocated to the axles. The sensor signals are subjected to a Fourier transformation in FFT units. The frequency profiles resulting from the Fourier transform are compared with profiles that are stored in memory. Differences that are detected are compared with threshold values and messages are correspondingly sent to the system that controls the vehicle. The monitoring system allows mechanical operating errors of the bogie to be detected independently of effects caused by the running surface upon which the vehicle travels.

Abstract: An apparatus for managing degree of compaction includes: a vehicle speed sensing means which senses a traveling speed of the vehicle; a vibration number setting means by which a number of vibrations of the roll transmitted per unit time is set; a reference vibration number setting means by which a reference number of vibrations of the roll transmitted per unit of longitudinal travel of the vehicle is set; a control means controlling electric signals outputted from the vehicle speed sensing means, the vibration number setting means, and the reference vibration number setting means, respectively; and an indicating means relatively and comparatively indicating, as a vehicle speed index value, magnitude relation of a current number of vibrations of the roll transmitted per unit of longitudinal travel of the vehicle relative to the reference number of vibrations of the roll on the basis of an electric signal outputted from the control means.

Abstract: An apparatus and method monitors the condition of a bearing/shaft assembly by forming diagnostics based on spectral analysis of assembly's vibration. Baseline parameters are determined by a microprocessor analysis of the vibration spectra, comparing actual peaks to the peaks predicted by a model. The microprocessor estimates rotation rate and preferably number of rolling elements by attempting to fit the model to the actual vibrational spectrum, by varying the assumptions. Baseline profiles are formed from one or more selected tones and preferably also harmonics thereof, to characterize the bearing/shaft assembly. The baseline profiles and parameters are compared against later acquired vibrational characteristics, and the comparison is used to diagnose bearing and/or shaft conditions.

Abstract: The invention has been developed to find out a blemish on the surface of a disk (in particular, a stroke mark in the CSS area) without opening up a hard disk. Furthermore, the invention is intended not to cause extra labor or cost in fabrication of hard disks, and to be applicable to hard disk already in widespread use. To this end, with an acoustic inspection method of the invention, inspection of whether or not a blemish has been inflicted on the surface of a disk (in particular, a blemish in the CSS area) can be conducted without opening up the hard disk by detecting vibration occurring when a head of the hard drive comes into collision with the blemish on the disk from vibration propagating to a housing of the hard disk.

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: A performance measuring system for a rotating shaft comprises a first annular support assembly to be coupled adjacent to a first end of a rotating shaft inwardly of associated shaft bearings. A second annular support assembly is to be coupled adjacent to a second end of a rotating shaft inwardly of associated shaft bearings. A third annular support assembly is to be coupled to the rotating shaft between the first and second support assemblies. A laser source is mounted on the first annular support assembly. A laser detector is mounted on the second annular support assembly. First and second magnetic sensors for detecting the Earth's magnetic field are mounted respectively on the first and second annular support assemblies. An accelerometer is mounted on the third annular support assembly for generating a fourth detection signal.

Abstract: A method and apparatus for compressing, storing and transmitting measurement data correlative to machine status is disclosed in which the measurement data is continuously sensed, sampled and processed to extract significant spectral elements including magnitude and phase information from each successive period of the originally measured data and to store those spectral elements in a memory means from an initial period of significant spectral elements and each successive period of significant spectral elements which have changed since the previous period for developing a compressed data history correlative to a continuous history of the status of the machine being monitored and from which continuous signals can be regenerated and analyzed for any earlier historical time.

Abstract: A machine protection system and method for rotating equipment introduces new alarming features and makes use of full proximity probe sensor information, including amplitude and phase. Baseline vibration amplitude and phase data is estimated and tracked according to operating modes of the rotating equipment. Baseline vibration and phase data can be determined using a rolling average and variance and stored in a unit circle or tracked using short term average and long term average baselines. The sensed vibration amplitude and phase is compared with the baseline vibration amplitude and phase data. Operation of the rotating equipment can be controlled based on the vibration amplitude and phase.

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 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 apparatus is proposed for judging the friction behavior between two counter-running partners, each of which has a contact surface, with the one contact surface moving along the other contact surface in the operating state. One of the contact surfaces is charged with ultrasonic signals (UI; UW), ultrasonic signals which are reflected by the contact surface are received as echo signals (ES), the echo signals (ES) are supplied to an evaluation unit as received signals, the Doppler shift of the received signals is determined by means of the evaluation unit, and the friction behavior between the counter-running partners is judged by means of the Doppler shift.

Abstract: A vibration monitor is provided which is worn on the wrist of an operative for an operating plant or apparatus. The monitor includes a piezoelectric transducer and associated circuitry which generates electronic digital signals during the periods when vibrations are experienced by the operative. Preferably, the plant or apparatus has a transmitter which transmits a code identifying the plant which is received by the monitor. Alternatively, the code may be entered manually. The monitor preferably includes a logger which can be connected to a host computer which data can be transferred over an external communications link. The logger includes a storage device for storing how long the operative is subjected to vibrations.

Abstract: Vibration data is transmitted from a remote site to a control facility using wireless data transmission. In one embodiment, the vibration signal is conditioned and digitized, and then sent via a page transmitter to the control facility.

Abstract: A hollow composite structure is inspected using an ultrasonic inspection apparatus including a yoke having a base, a first arm extending from the base, and a second arm extending from the base parallel to the first arm. A first ultrasonic transducer is affixed to the first arm, and a second ultrasonic transducer is affixed by a spring mount to the second arm in facing relation to the first ultrasonic transducer. A retractor is affixed to the spring mount to permit the second ultrasonic transducer to be retracted away from the first ultrasonic transducer against a spring bias. The ultrasonic inspection apparatus is positioned by placing one of the arms adjacent to the interior surface, one of the arms adjacent to the exterior surface, and the base extending through the access opening.

Abstract: A method of characterizing the vibration of a plurality of rotating blades (12), such as turbine blades in a gas turbine engine, includes the steps of providing a single strain gauge (16A) on a single one (12A) of the blades and providing either one or two tip timing probes (22A, 22B) on a casing surrounding the blades. The data from the strain gauge (16A) allows the vibration of the single blade (12A) to be fully characterized while the data from the tip timing probes (22A, 22B) allows the amplitudes or velocities of vibration of all the blades to be determined. The relationship between the data from the tip timing probes for the single blade (12A) and the stress data from the strain gauge may be established. This relationship may then be assumed to apply to all the blades, thus allowing the stresses induced in all the blades by the vibrations to be determined.

Abstract: A method for visualizing and indicating characteristics of vibration measurement data for a rotating or vibrating object. Specific components are removed from the measurement data or are minimized therein. After removing or minimizing the specific component, the measurement data is indicated in a Campbell diagram.

Abstract: Rolling stock equipment is disclosed that has a predictive diagnostic system to enable condition-based maintenance. The rolling stock equipment has vibration transducers on key equipment. Data from the transducers is periodically sampled. The data is analyzed to determine if a fault condition exists by comparing the vibration signatures to defined threshold levels. If a threshold level is exceeded, a fault warning is produced to alert maintenance staff that preventative maintenance should be performed.

Abstract: A system for measuring the rotational speed of a shaft driven by a motor. The system includes a rotation measurement device having a rotatable sensor and configured to generate a signal corresponding to rotation of the sensor. The rotation measurement device may be supported by a fixture mountable on the motor. A coupler is associated with the sensor and includes a gripping surface configured to contact and grip the end-surface of the shaft to couple the sensor to the shaft and impart the rotation of the shaft to the sensor.

Abstract: A diagnostic technique for monitoring shaft cracking or incipient pinion slip involves monitoring a shift in a characteristic natural frequency of an operating system such as a geared system of a locomotive. The technique involves monitoring a shift in the characteristic natural frequency or resonance of a shaft for detecting shaft cracking. The technique also involves monitoring a shift in the characteristic natural frequency of one or more assemblies of the operating system which include a pinion and detecting a shift in the one or more characteristic natural frequencies of the assemblies. A vibration sensor or measurement of current changes of a motor of the operating system can be used to detect vibrations to monitor the characteristic natural frequencies. Torsional oscillations or measurement of current and voltage changes of a motor of the operating system, can also be used to monitor the characteristic natural frequencies.

Abstract: A method and apparatus for determining severity of a trend toward an impending machine failure under actual operating conditions. The method and apparatus includes providing a typical failure trend based on a set of normal operating conditions for the machine, determining a slope value for the typical failure trend, determining a slope value for the trend toward the impending machine failure under the actual or proposed operating conditions, determining a weight value for at least the actual or proposed operating conditions, and determining the severity as a function of the slope values and the weight value.

Abstract: A capacitance probe measures and tracks frequency and amplitude changes of a component during a high cycle fatigue portion of a life test. The probe includes an internal oscillator, an adjustable receiver circuit, a product detector, and a pair of gain amplifiers. The oscillator generates a single controlled frequency output. The receiver circuit receives the frequency and creates a DC voltage shift that nulls the capacitance bridge. The product detector detects an amplitude modulated product of the oscillator and rejects undesirable frequencies. The gain amplifiers detect a DC voltage shift and permit the capacitance effect to be easily nulled.

Abstract: The present invention relates to measuring equipment (1) that includes at least two sensors (2, 3), each being adapted to sense a measurement magnitude, a measuring card (6) to which said sensors (2, 3) are coupled, and a computer unit to which the measuring card is coupled. At least one of the sensors (2) is adapted to sense prevailing frequencies of an object (11) to be measured. At least one of the sensors (3) is adapted to evaluate prevailing tacho-pulses of an object (11) to be measured. The circuits in said measuring card (16) are adapted to evaluate prevailing sound and vibrations generated by the rotating object (11) in response to information received with respect to prevailing frequency and prevailing tacho-pulses, by dividing the time distance between two tacho-pulses into a number of sub-sections and generating a circuit-internal tacho-signal for each sub-section.

Abstract: Within the scope is a method for detecting the variator slip in continuously variable transmission (CVT transmission). The tribologic slip is detected by monitoring a rotating variator according to vibration and a subsequent evaluation.

Abstract: A method of measuring the vibration of an actuator assembly in a disc drive in the plane of rotation of the actuator assembly and determining the resonance behavior of the actuator assembly from the measured vibrations is disclosed. The method involves use of a laser to measure the vibrational behavior of the actuator assembly in the rotational plane. A method is described for adjusting the resonance behavior of the actuator assembly during the manufacturing process without the use of glue or extra parts. The resonance behavior is determined and the preload on the bearings in the actuator assembly is adjusted until a desired resonance behavior is achieved.

Abstract: Rotors, especially elastic rotors, are balanced by measuring unbalance values which provide information regarding the size, or rather the weight of balancing weights and the angular location where these balancing weights are to be secured to the rotor. For obtaining balancing weights an excitation force is applied to the rotor which is at a standstill or which may, but does not have to, rotate when the excitation force is applied by a hammer (11), equipped with a sensor (S) and an output (11A) to provide excitation force spectra. Further sensors (7, 8) are positioned in bearing planes (ME1, ME2) and provide response force spectra. The excitation force spectra and the response force spectra due to the rotating unbalanced rotor are then processed to obtain the unbalance compensating values required for the balancing operation.

Abstract: A device for detecting undesirable vibrations in a vehicle drive line utilizes a sensor that communicates with a controller to indicate undesirable vibrations in a drive line component. In one example, a temperature sensor is placed in a central portion of a universal joint. The temperature sensor preferably is supported within a single housing along with a transmitter that is responsive to the temperature sensor to transmit a signal to a remotely located receiver without using a hardwire connection between the transmitter and receiver. Packaging the temperature sensor, transmitter and a power source within a single housing provides the ability to seal off or close a series of lubrication channels that extend through the universal joint. In another example, a contact-based sensor provides a signal whenever a vibration of a drive line component occurs.

Abstract: An apparatus and method for testing vibration in a bladed disk includes a motor-driven rotor upon which the bladed disk can be attached. At least one nozzle coupled with a liquid source is positioned to direct liquid from the liquid source to a position where it would impact at least one blade of the rotating bladed disk. The stress state and/or position of a rotating blade, so impacted, can be monitored to test its vibration characteristics.

Abstract: An apparatus and method monitors the condition of a bearing/shaft assembly by forming diagnostics based on spectral analysis of assembly's vibration. Baseline parameters are determined by a microprocessor analysis of the vibration spectra, comparing actual peaks to the peaks predicted by a model. The microprocessor estimates rotation rate and preferably number of rolling elements by attempting to fit the model to the actual vibrational spectrum, by varying the assumptions. Baseline profiles are formed from one or more selected tones and preferably also harmonics thereof, to characterize the bearing/shaft assembly. The baseline profiles and parameters are compared against later acquired vibrational characteristics, and the comparison is used to diagnose bearing and/or shaft conditions.

Abstract: A method for determining a minimal set of adjustments for the blades of a rotor supported by a supporting structure for reducing rotation-induced vibration in the supporting structure at at least one harmonic rotation order and/or for reducing track deviation while maintaining structure vibration over at least one harmonic order within an acceptable limit. In one embodiment, a relationship is established by which vibration of the supporting structure may be calculated at harmonic orders of rotor rotation from Fourier coefficients of adjustment, Fourier coefficients of unit vibration influence and Fourier coefficients of vibration measurements. Thereafter, a value is determined for each selected Fourier coefficient of adjustment that provides a desired virtual reduction of vibration of the supporting structure at the harmonic order of the selected Fourier coefficient of adjustment using the vibration relationship.

Abstract: A MEMS-based system that enables low cost, low power, single chip realization of real-time signal detection and fault diagnosis. The system is suitable for analyzing the time-varying properties of a signal that are important for condition-based monitoring of electro-mechanical machines or structures. The system includes mechanical sensors that sense input signals such as vibration, signal templates of fault conditions, logic units that detect, store, and compare signal features to provide a diagnostic state, and an output readout mechanism to couple the diagnostic state to readout device that provides an external signal.

Abstract: An apparatus for detecting and transmitting impact data is disclosed for use in monitoring early-stage development of harmful mechanical conditions for reciprocating machinery. The impact transmitter device includes a single self-contained unit having a stainless steel housing which contains an impact accelerometer, a detector circuit, a measurement and timing circuit, a 4-20 mA driver circuit, independent polarity circuit, and an electromagnetic impulse protection unit. The impact transmitter device further includes a field adjustable static threshold defining the severity of the impact detected, and a field adjustable reference time window interval. The variable severe impact level threshold allows an operator to isolate severe impacts from typical machine vibration. The variable time window interval allows an operator to synchronize the present invention with different machine speeds and to collect severe impact data over an appropriate time frame.

Abstract: The present invention concerns a method and device for detecting an imbalance condition in a rotating washing machine tub. An indication of a power level required to maintain a given washing machine rotation speed is compared to a predefined standard power level associated with the given rotation speed, and a tub imbalance condition is detected in response to the comparison. The predefined standard power level may be stored in a memory device accessible by a processor that is programmed to calculate the power level required to achieve the given washing machine rotation speed and compare the required power level to the predefined standard power level to detect the tub imbalance condition.

Abstract: A high-speed bearing vibrational analysis system for testing a bearing includes a bearing holding member to accommodate a shaft and the bearing. The bearing holding member is adapted to rotate the bearing at high-speeds. The shaft is inserted into an accommodation portion of the bearing holding member. A vibration sensor is in contact with the bearing to detect vibrations of the bearing, while it is rotated at high speeds, and to transmit data for analysis. A computer system is provided for executing a software program that receives and analyzes the data from the vibration sensor.

Abstract: An apparatus for testing at least one joint includes an articulation device and a defect detection system. The first joint being tested has an inner race rotatably mounted within an outer race, a driving shaft connected to either the inner race or outer race, and a load bearing shaft connected to the other one of the inner race or outer race. The articulation device connects to the driving shaft and articulates the driving shaft to articulate the first outer race with respect to the first inner race without rotating the driving and load bearing shafts. The defect detection system detects first signals from the first joint during the articulation of the first outer race with respect to the first inner race and determines if there is a defect in the first joint based on the detected first signals.

Abstract: The vibration damping capability of a test part can be computed by vibrating the test part at different frequencies, and measuring the amplitude of the vibrational wave generated in the test part at each input frequency. The test data can be used to generate a measurement curve plotting vibration amplitude against frequency.

Abstract: A method for determining the operational condition of a rotary machine is disclosed. The method comprises the steps of monitoring the machine under a baseline operating condition and collecting baseline vibrational data. A preselected number of baseline parameters are calculated from the baseline vibrational data. Next, a first baseline operational indicator is calculated from the baseline parameters, and the baseline parameters and the first baseline operational indicator are stored in a memory location. The machine is then monitored under a subsequent operating condition, and subsequent vibrational data is collected during the subsequent operating condition. A preselected number of subsequent operating parameters is calculated from the subsequent vibrational data, and a first subsequent operational indicator is calculated from the preselected number of subsequent operating parameters. Finally, the baseline data is compared to the subsequent operating data to determine the condition of the machine.

Abstract: A hand-held data collection and analyzing unit for collecting and analyzing vibration data induced by a rotating shaft including a processor that first converts the analog vibration signal into corresponding digital vibration samples. Thereafter, the processor provides in response to the digital vibration samples, corresponding output vibration samples in which samples within each set of output vibration samples are provided at a rate that varies as a function of variations in the speed of the rotating shaft. A digital processor then collects a time waveform record in response to a plurality of the output vibration samples, wherein the sample rate for the output vibration samples collected in the time waveform record varies as a function of variations in the speed of the rotating shaft.

Abstract: The present invention provides a device and method for determining the stable speeds for a rotating milling tool by non-cuttingly exciting the milling tool, by vibrating the milling tool, and measuring how the milling tool is excited. The present invention also provides a device and method for determining the stable speeds for a lathe tool by non-cuttingly exciting the lathe tool, by vibrating the tool using an excitation device mounted on a rotating lathe test bar, and measuring how the lathe tool is excited.

Abstract: An apparatus for detecting ultrasonic energy generated by a mechanical device and for applying lubricant to the device is presented. The apparatus includes a lubrication tool, such as a grease gun, which has a lubrication delivery element for delivering lubrication to the mechanical device. An ultrasonic transducer is contained in a housing which is removably attached to the outside of the lubrication delivery element. The housing is configured to acoustically isolate the transducer from the lubrication tool. An acoustic waveguide depending from the housing is provided to carry ultrasonic energy from the device to the transducer when the lubrication tool is applied to the device. An electrical circuit, which may be attached to the lubrication device, produces an output signal which indicates the magnitude of detected ultrasonic energy.

Abstract: Device and method for detecting anomaly of an air conditioner, the method including the steps of (1) detecting an acoustic emission signal from a compressor in the air conditioner during operation of the air conditioner, (2) detecting parameters of particular components from the detected acoustic emission signal, and (3) comparing the detected parameters to respective references, to determine anomaly of the air conditioner on the whole, whereby permitting the most reliable detection of anomaly of the air conditioner.

Abstract: The present invention concerns a method and device for detecting an imbalance condition in a rotating washing machine tub. An indication of a power level required to maintain a given washing machine rotation speed is compared to a predefined standard power level associated with the given rotation speed, and a tub imbalance condition is detected in response to the comparison. The predefined standard power level may be stored in a memory device accessible by a processor that is programmed to calculate the power level required to achieve the given washing machine rotation speed and compare the required power level to the predefined standard power level to detect the tub imbalance condition.

Abstract: A signal analysis system and method for analyzing an input signal acquired from a mechanical system. The mechanical system may include at least one rotating apparatus. The signal analysis system may be configured to: (a) receive samples of the input signal, (b) perform an invertible joint time-frequency transform (e.g. a Gabor transform) on the samples of the input signal to produce a first array of coefficients which depend on time and frequency, (c) select first coefficients from the first array which correspond to a first subset of one or more order components in the input signal, (d) generate a time domain signal from the first coefficients, and (e) present the time domain signal to a user on a presentation device. The signal analysis system generate the time domain signal from the first coefficients by performing an inverse joint time-frequency transform on the first coefficients.

Abstract: A method for determining system parameters, such as the operating speed, working pressure and pivot angle of an axial piston unit in which the operating speed, working pressure and pivot angle are determined by means of a frequency analysis of a detected solid-borne sound signal from an axial piston unit of a hydrostatic drive mechanism. A liquid-borne sound signal of airborne sound signal can be used, in which case a respective system parameter is determined by means of a frequency analysis of a detected liquid-borne sound signal or airborne sound signal from the axial piston unit.

Abstract: An apparatus and method monitors the condition of a bearing/shaft assembly by forming diagnostics based on spectral analysis of assembly's vibration. Baseline parameters are determined by a microprocessor analysis of the vibration spectra, comparing actual peaks to the peaks predicted by a model. The microprocessor estimates rotation rate and preferably number of rolling elements by attempting to fit the model to the actual vibrational spectrum, by varying the assumptions. Baseline profiles are formed from one or more selected tones and preferably also harmonics thereof, to characterize the bearing/shaft assembly. The baseline profiles and parameters are compared against later acquired vibrational characteristics, and the comparison is used to diagnose bearing and/or shaft conditions.

Abstract: An arrangement for detecting the turbocharger rotational speed on internal-combustion engines is provided with at least one piezoelectric acceleration sensor fixed on the turbocharger and with an analyzing circuit having an analog filter arrangement for filtering the output signals of the acceleration sensor. The output signals of the filter arrangement are fed by way of a frequency-to-voltage converter in the form of an analog voltage, or directly in the form of frequency signals, as input signals to an electronic control unit of the internal-combustion engine or to a measuring and/or display unit. As a result, the turbocharger rotational speed can be detected at a reasonable cost with a small and robust arrangement suitable for mass production and requiring no constructional changes on the turbocharger.

Abstract: The invention relates to an ultrasonic measuring instrument comprising a housing which contains a transducer for transmitting and receiving ultra-sound waves, and a rotatable mirror placed inside the housing for directing ultra-sound waves coming from the transducer through a tapering window comprised in the housing to an object of measuring outside the housing, and for directing ultra-sound waves which are reflected by the object of measuring and which enter the housing through the window to the transducer. Around, and rotating with the mirror a tube is provided, comprising a recess for the passage of ultra-sound waves.

Abstract: A diagnostic system includes a vibration sensor mounted on a machine to measure vibrations. Vibration signals from the sensor are processed and analyzed by the system. From a known critical frequency of a vibration-generating component, the system measures the amplitude of the vibration signal at more than one harmonic frequency of the known critical frequency and compares the amplitudes to amplitudes at adjacent harmonic frequencies. When a relatively large amplitude is found at a harmonic frequency, that is a harmonic frequency near a resonant frequency of the physical path between the vibration sensor and the vibration-generating component, the system analyzes the shape and magnitude of the vibration signal around that harmonic frequency to evaluate the condition of the machine.

Abstract: A method and system for detecting an imbalance condition in a rotating washing machine tub includes receiving an indication of the actual tub rotation speed, comparing the actual tub rotation speed to a predetermined desired rotation speed to calculate a speed error, and determining maximum and minimum speed errors. The difference between the maximum and minimum speed error is calculated, and a tub imbalance condition is detected based at least in part on the calculated difference. In one embodiment, the speed error is input to a controller that produces an output used to minimize the absolute speed error. The difference between the minimum and maximum controller output is then used to determine tub imbalance. In another aspect of the invention, the method and system include receiving an indication of a power level required to achieve a given washing machine rotation speed and comparing the required power level to a predefined standard power level associated with the given rotation speed.

Abstract: A device for conditioning the electrical signal generated by a vibration sensor for use of the conditioned signal by a computer-based data acquisition system utilizes a support body and circuitry for performing a series of operations upon the sensor-generated signal. The circuitry includes an input stage for receiving and amplifying the electrical signal generated by the vibration sensor to thereby develop an output electrical signal of the input, and further includes a gain stage for receiving and AC coupling the output electrical signal of the input stage and amplifying the output signal of the input stage by a predetermined factor and thereby developing an output electrical signal of the gain stage.