Method and apparatus for analyzing and detecting faults in bearings and other rotating components that slip
First Claim
1. A method for analyzing an operating rotary machine having interacting components that slip, said interacting components comprising at least a first component rotating asynchronously with respect to a second component, said first component being an asynchronous component and said second component being a synchronous component comprising the steps of:
- a. acquiring a machine signal from said rotary machine, said machine signal having a plurality of interaction elements generated by said interacting components;
b. conditioning said machine signal to produce a conditioned signal;
c. processing said conditioned signal by forming products of certain ones of said elements for providing a processed signal phase locked to said synchronous component;
d. averaging said processed signal over a plurality of data records to produce an averaged signal comprised of averaged signal elements; and
e. analyzing said averaged signal elements for locating extrema of said averaged signal thereby determining attributes of said asynchronous component.
1 Assignment
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Accused Products
Abstract
The present invention provides a method and system for analyzing signals from rotating machines containing rotating components that slip and, thereby, to detect faults in those components. The signals are processed by a series of steps to generate coherently averaged spectra and derived features that indicate defects in, or certain other features of, machine components that slip or rotate asynchronously.
98 Citations
43 Claims
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1. A method for analyzing an operating rotary machine having interacting components that slip, said interacting components comprising at least a first component rotating asynchronously with respect to a second component, said first component being an asynchronous component and said second component being a synchronous component comprising the steps of:
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a. acquiring a machine signal from said rotary machine, said machine signal having a plurality of interaction elements generated by said interacting components; b. conditioning said machine signal to produce a conditioned signal; c. processing said conditioned signal by forming products of certain ones of said elements for providing a processed signal phase locked to said synchronous component; d. averaging said processed signal over a plurality of data records to produce an averaged signal comprised of averaged signal elements; and e. analyzing said averaged signal elements for locating extrema of said averaged signal thereby determining attributes of said asynchronous component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for analyzing a machinery signal X(t) generated by machinery in which a component A is physically associated with at least one rotating component B, comprising the steps of:
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a. sensing said machinery signal X(t), where t represents time, containing signal components generated by said components A and B; b. performing signal conditioning on said machine signal X(t); c. obtaining a signal Y(t) formed of a pulse train with a fixed number of pulses per rotation of said component B; d. digitizing said machinery signal X(t) where said pulses comprising signal Y(t) are used as an external clock to control digitizing; e. enhancing said machinery signal X(t) to form signal X'"'"'(t); f. forming equal length data records by sampling from said signal X'"'"'(t), said data records being initialized at a fixed angular orientation of said rotating component B; g. performing a Discrete Fourier Transform (DFT) on each said data records, giving rise to a series of complex components of said DFT; h. forming for said DFT a spectral function G from the products of pairs of said complex components of said DFT or its complex conjugates such that the sum or difference of the respective frequencies of said complex components is constant and equal to some harmonic of the rotation frequency of said component B; i. averaging said spectral function G over M data records to form an averaged function <
G>
;j. analyzing said averaged function <
G>
to determine attributes of said component A. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for analyzing a machinery signal X(t) generated by machinery in which component A is physically associated with at least one rotating component B, comprising the steps of:
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a. sensing said machinery signal X(t), where t represents time, containing signal components generated by said components A and B; b. performing signal conditioning on said signal X(t); c. digitizing said signal X(t), forming data records of equal length, performing DFT analysis of said data records to form a DFT and forming a spectrum G by multiplication of pairs of complex components of said DFT or its complex conjugates such that a sum or difference of representative frequencies of said pairs of complex components is a constant and approximately equal to a specific harmonic of a frequency of rotation of said component B; d. obtaining a DFT signal component for a specific harmonic of said frequency of rotation of said machine component B, calculating a complex conjugate of a complex component of said DFT component for said specific harmonic and multiplying by spectrum function G to obtain a function Go ; e. averaging said function Go over M of said data records to form an averaged function <
Go >
;f. analyzing said averaged function <
Go >
for attributes of said rotating component B. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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33. A device for analyzing signals from a rotating or cyclic machine in which a first component of said machine has a frequency of rotation and is physically associated with at least one rotating second component, said device comprising:
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a sensor coupled to said machine; an interface connected to said sensor; conditioning means connected to said interface for conditioning said signal to produce a conditioned signal; digitizing means for digitizing said conditioned signal; pulsed signal means for controlling said digitizing means to produce a fixed number of digitized samples per turn of said second component; computer means for capturing fixed length data records, said records comprised of a constant number of said digitized samples in which the first said digitized sample of each of said fixed length data records occurs at a fixed angular orientation of said second component, and performing a Discrete Fourier Transformation (DFT) analysis of said data records; forming a spectrum function G by multiplying pairs of components of said DFT or DFT complex conjugates to produce multiplied pairs such that the sum or difference of the respective frequencies of each of said multiplied pairs is a constant and approximately equal to a specific harmonic of said frequency of rotation of said second component; means for averaging said multiplied pairs over predetermined ones of said data records; means for analyzing said spectrum function G for attributes; and output means for displaying the results of said analysis. - View Dependent Claims (34, 35, 36, 37, 38)
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39. A method for analyzing an operating rotary machine having interacting components, said interacting components comprising at least a first component rotating asynchronously with respect to a second component, said first component being an asynchronous component and said second component being a synchronous component comprising the steps of:
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a. acquiring a machine signal from said rotary machine, said machine signal having a plurality of interaction elements generated by said interacting components; b. conditioning said machine signal to produce a conditioned signal; c. processing said conditioned signal by forming products of certain ones of said signal elements for providing a processed signal phase locked to said synchronous component; d. averaging said processed signal over a plurality of data records to produce an averaged signal comprised of averaged signal elements; and e. analyzing said averaged signal elements for locating extrema of said averaged signal thereby determining attributes of said asynchronous component; wherein the frequency locations of certain of said attributes are used to calculate other attributes of said asynchronous components, said attributes including relative diameters of bearing components and the number of elements in a rolling element bearing.
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40. A method for analyzing a machinery signal X(t) generated by machinery in which a component A is physically associated with at least one rotating component B, comprising the steps of:
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a. sensing said machinery signal X(t), where t represents time, containing signal components generated by said components A and B; be performing signal conditioning on said machine signal X(t); c. obtaining a signal Y(t) formed of a pulse train with a fixed number of pulses per rotation of said component B; d. digitizing said machinery signal X(t) where said pulses comprising signal Y(t) are used as an external clock to control digitizing; e. enhancing said machinery signal X(t) to form signal X'"'"'(t); f. forming equal length data records by sampling from said signal X'"'"'(t); g. performing a Discrete Fourier Transform (DFT) on each said data records, giving rise to a series of complex components of said DFT; h. forming for said DFT a spectral function G from the products of pairs of said complex components of said DFT or its complex conjugates such that the sum or difference of the respective frequencies of said complex components is constant and equal to some harmonic of the rotation frequency of said component B and the phase of the products of pairs is constant and independent of the initial angular orientation of said rotating component B; i. averaging said spectral function G over M data records to form an averaged function <
G>
;j. analyzing said averaged function <
G>
to determine attributes of said component A;wherein in said step f, said data records do not begin at said fixed angular orientation of said rotating component B.
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41. A method for analyzing a machinery signal X(t) generated by machinery in which a component A is physically associated with at least one rotating component B, comprising the steps of:
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a. sensing said machinery signal X(t), where t represents time, containing signal components generated by said components A and B; performing signal conditioning on said machine signal X(t); c. obtaining a signal Y(t) formed of a pulse train with a fixed number of pulses per rotation of said component B; d. digitizing said machinery signal X(t) where said pulses comprising signal Y(t) are used as an external clock to control digitizing; e. enhancing said machinery signal X(t) to form signal X'"'"'(t); f. forming equal length data records by sampling from said signal X'"'"'(t), said data records being initialized at a fixed angular orientation of said rotating component B; g. performing a Discrete Fourier Transform (DFT) on each said data records, giving rise to a series of complex components of said DFT; h. forming for said DFT a spectral function G from the products of pairs of said complex components of said DFT or its complex conjugates such that the sum or difference of the respective frequencies of said complex components is constant and equal to some harmonic of the rotation frequency of said component B; i. averaging said spectral function G over M data records to form an averaged function <
G>
;j. analyzing said averaged function <
G>
to determine attributes of said component A;wherein in said step h said pairs of said components to be multiplied in forming said function G are complex and are formed of a first and second complex component, said first complex component is produced from said baseband range of frequencies and said second complex component is produced from said bandpassed range of frequencies or both said first and second complex components are produced from said range of baseband frequencies or both said first and second complex components are produced from said range of bandpassed frequencies.
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42. A method for analyzing a machinery signal X(t) generated by machinery in which a component A is physically associated with at least one rotating component B, comprising the steps of:
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a. sensing said machinery signal X(t), where t represents time, containing signal components generated by said components A and B; b. performing signal conditioning on said machine signal X(t); c. obtaining a signal Y(t) formed of a pulse train with a fixed number of pulses per rotation of said component B; d. digitizing said machinery signal X(t) where said pulses comprising signal Y(t) are used as an external clock to control digitizing; e. enhancing said machinery signal X(t) to form signal X'"'"'(t); f. forming equal length data records by sampling from said signal X'"'"'(t), said data records being initialized at a fixed angular orientation of said rotating component B; g. performing a Discrete Fourier Transform (DFT) on each said data records, giving rise to a series of complex components of said DFT; h. forming for said DFT a spectral function G from the products of pairs of said complex components of said DFT or its complex conjugates such that the sum or difference of the respective frequencies of said complex components is constant and equal to some harmonic of the rotation frequency of said component B; i. averaging said spectral function G over M data records to form an averaged function <
G>
;j. analyzing said averaged function <
G>
to determine attributes of said component A;in which said component A is a rolling element bearing and the frequency locations of said attributes in step j are used to calculate the geometric ratio of the race diameters or the relative magnitudes of said attributes are used to determine the number of rolling elements in said rolling element bearing.
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43. A method for analyzing a machinery signal X(t) generated by machinery in which component A is physically associated with at least one rotating component B, comprising the steps of:
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a. sensing said machinery signal X(t), where t represents time, containing signal components generated by said components A and B; b. performing signal conditioning on said signal X(t); c. digitizing said signal X(t), forming data records of equal length, performing DFT analysis of said data records to form a DFT and forming a spectrum G by multiplication of pairs of complex components of said DFT or its complex conjugates such that a sum or difference of representative frequencies of said pairs of complex components is a constant and approximately equal to a specific harmonic of a frequency of rotation of said component B; d. obtaining a DFT signal component for a specific harmonic of said frequency of rotation of said machine component B, calculating a complex conjugate of a complex component of said DFT component for said specific harmonic and multiplying by spectrum function G to obtain a function Go ; e. averaging said function Go over M of said data records to form an averaged function <
Go >
;f. analyzing said averaged function <
Go >
for attributes of said rotating component B;wherein said component A is a rolling element bearing and frequency locations of said attributes of said function G are used to calculate the geometric ratio of the inner and outer race diameters or the relative magnitudes of said attributes are used to determine the number of rolling elements in said bearing.
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Specification