General Electric Company

Electric Power Research Institute Incorporated

Rudolph A Koegl

Gerald Burt Kliman

William James Premerlani

Richard A Hogle

John P Keaveney

David Jeremiah Hoeweler

John Erik Hershey

Jeffrey Wayne Eberhard

James Patrick Lyons

Kristina H Hedengren

John Raymond Krahn

Aiman A Abdel-Malek

Douglas S Steele

David W Oliver

Albert Andreas Esser

Charles Robert Wojciechowski

Ralph Gerald Isaacs

Joseph Czechowski, Iii

Steven D Hansen

George Edward Williams

Joseph Manuel Portaz

Stephen E Grabkowski

John Robert Brehm

Max W Schulz, Jr

Theodore W Sippel

Joseph J Sostarich

Henry J Scudder, Iii

Thomas G Kincaid

James M Brown, Jr

Richard D Miller

Susan D Bauer

Mark Gerald Adamiak

James W Schuler

Larry C Howington

An integrated motor monitoring system collects, analyzes, and stores to database(s) on-line and off-line coordinated real-time motor data for industrial AC and DC motors. On-line coordinated real-time motor data from both on-motor sensors and remote sensors at a motor control center are collected simultaneously and processed. Off-line measurements are performed with integrated stimulus and measurement apparatus. Monitoring units at the motor and motor control center each collect specific data on the motor. The database provides current and historical data on the motor for analyses conducted at the motor or at the motor control center. Additionally the motor monitoring system has the capability of relating motor system or process events with motor performance.

Electrical motor monitoring system and method

A method for obtaining a power system phasor includes sampling a power system signal at instants determined by a nominal power system frequency to provide a plurality of data samples; using the data samples to estimate a phasor having an elliptical trajectory; generating a deviation formula representing a frequency deviation between actual and nominal power system frequencies; and using the deviation formula to perform a coordinate transform of the estimated phasor to provide a scaled phasor having a substantially circular trajectory. If the data samples are unevenly spaced, a method in another embodiment includes minimizing squares of errors between the unevenly spaced data samples and an approximating sinusoidal function of the data samples. Power system phasors can be used to detect turn faults by providing scaled current and voltage phasors; extracting fundamental voltage and current phasors; and applying a symmetrical component transform to the fundamental voltage and current phasors to obtain symmetrical component voltage and current phasors for use in determining the existence of a turn fault. Variance calculations and/or trigonometric function fits can be used to increase sensitivity of fault detection.

Method and apparatus for compensation of phasor estimations

A method for monitoring a rotor speed of an X-ray tube anode drive includes acquiring axial flux pickup data from the rotor, using the axial flux pickup data to provide a flux spectrum, and estimating the rotor speed by analyzing the flux spectrum. The step of acquiring axial flux pickup data can include situating an axial leakage flux pickup coil so as to pick up a flux signal from an X-ray tube anode drive rotor while the rotor rotates. An analog flux signal can be converted to a digital flux signal and a fast Fourier transform can be used to transform the digital flux signal into a flux spectrum. The flux spectrum can be used to estimate a drive frequency and a slip frequency and the speed can be estimated by subtracting the slip frequency from the drive frequency and dividing by the number of pole pairs of the X-ray tube anode drive.

X-ray tube anode drive speed monitor including flux pickup coil

A method for detecting turn faults in an induction motor includes obtaining motor current and voltage waveforms and converting the motor current and voltage waveforms to digitized current and voltage waveforms. Fundamental phasors of the digitized current and voltage waveforms are extracted and, a symmetrical component transform is applied to the fundamental phasors to obtain symmetrical component current and voltage phasors including a negative sequence voltage phasor (V.sub.-) and negative sequence current phasor (I.sub.-). A fault injected negative sequence current (Ii.sub.-) is estimated according to the following equation:

Self-tuning and compensating turn fault detector

A signal processing system includes a phase locked loop for locking a largest sine wave phase and frequency element of an incoming analog signal; an amplitude estimator for estimating a maximum amplitude of the incoming signal; a multiplier for multiplying the estimated largest sine wave phase and frequency element by the estimated maximum amplitude to provide an estimated largest sine wave component; and a subtractor for subtracting the estimated largest sine wave component from the incoming signal to provide a diagnostic signal.

Motor current signal processor using analog substraction of an estimated

Motor current and voltage waveforms are measured and converted to digitized current and voltage waveforms. A weighted discrete fourier transform is applied to the digitized current and voltage waveforms to obtain negative sequence current and voltage phasors; and the negative sequence current and voltage phasors are used to determine the existence of a turn fault. The use of the negative sequence current and voltage phasors can be performed by employing one of several techniques. In a first embodiment, an apparent negative sequence impedance is estimated by dividing the negative sequence voltage phasor by the negative sequence current phasor for comparison with a threshold negative sequence impedance. In a second, related embodiment, a current differential is estimated by dividing the negative sequence voltage phasor by a characteristic negative sequence impedance and subtracting the result from the negative sequence current phasor for comparison with a threshold current differential. In a third, related embodiment, a voltage differential is estimated by multiplying the negative sequence current phasor by a characteristic negative sequence impedance and subtracting the result from the negative sequence voltage phasor for comparison with a threshold voltage differential. In either of the second or third embodiments, the characteristic negative sequence impedance can be obtained by inserting a calibration device into one phase of the motor.

Stator turn fault detector for AC motor

Laser drilling and real-time sensing and control of hole depth by the provision of magnetic field jack-up coils located around or to the side of a laser beam, in a stream of ionized plasma, and the coils are connected to a depth detector and comparator to halt laser drilling at a desired depth.

Inductive depth sensing and controlling method and system for laser

Detection of the breakthrough of a laser beam through a workpiece wall uses one or more magnetic field pick-up coils. The coils are disposed on the drill side (side upon which the laser beam is impinging) of the workpiece. The coils sense the magnetic fields generated in the ionized plasma of particles escaping from the impact of the laser on the surface. The coils are connected to a breakthrough detector which generates a breakthrough signal upon the plasma and associated magnetic fields disappearing at breakthrough. The breakthrough signal is used to turn off the laser and/or change the application point at which the laser beam strikes the workpiece.

Real-time magnetic-flux breakthrough detection method and system for

The quality of x-ray images is significantly enhanced by adjusting the x-ray system operating parameters in real time during acquisition of x-ray data to take information about the part into account adaptively. X-ray energy, x-ray flux, and integration time can all by varied independently and in combination to improve the signal to noise ratio in the image. The x-ray data from a previous subsection of the image is processed to determine optimum system operating parameters for a next image subsection. x-ray tube voltage is adjusted to change x-ray energy and keep .alpha.L close to 2 over all image subsections. X-ray tube current is adjusted to change x-ray flux and data acquisition integration time is adjusted to keep the signal to noise ratio within limits.

Adaptive enhancement of x-ray images

An X-ray inspection system for manually or automatically performing digital fluoroscopy inspections and/or computed tomography inspections by X-ray examination of manufactured parts incorporates a computer system which automatically analyzes the inspected parts for flaws. The system includes apparatus for automatically positioning the parts in an X-ray machine for obtaining fluoroscopy and tomography views of the part and for acquiring data from the inspections at production rates. The system automatically identifies the location of rejectable flaws in the parts during the fluoroscopy scanning and subsequently identifies those locations for obtaining tomography scans, if the identified flaw location is questionable. The system can automatically reject parts containing flaws identified during the fluoroscopy inspections. This system operates in a real-time environment by providing analysis of one part while a subsequent part is being subjected to X-ray examination. The data obtained during each examination is archived and stored for tracking the part in further manufacturing processes.

X-ray inspection system

A method and apparatus for detecting rotor faults in an induction motor. A flux sensor generates a flux signal corresponding to the magnetic flux at a predefined flux detection point external to the motor. A current sensor generates a current signal proportional to the current drawn by said motor. A time series of data points is stored, representing the values of the flux signal and the current signal over a period of time. The time series are transformed by FFT into a set of flux spectra and into a set of current spectra. Then the line frequency of the motor's power supply is determined by finding the maximum of the current spectra. Similarly, the slip frequency of the motor is determined by finding the maximum of the flux spectra in a predefined spectral range (e.g., below 2 Hz). The analysis of the rotor is then performed by comparing the amplitude of the current spectra, at a set of rotor fault harmonic frequencies, with specified fault threshold criteria. Each rotor fault harmonic frequency is a predefined function of the line frequency and the slip frequency. The presence of a rotor fault is denoted if the amplitude of any of said current spectra exceed a corresponding fault threshold criteria.

Rotor fault detector for induction motors

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Niskayuna, NY, United States of America

Rudolph A Koegl