US6199023B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for removing spurious signatures in motor current signature analysis
Assignee: General Electric Co
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Filing: 1998-11-16
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Granted: 2001-03-06
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Expires: 2018-11-16
Abstract
Abstract A method for removing spurious signals in a process of motor current signature analysis of an electric motor ( 24 or 33 ) includes creating an electronic model of the motor, acquiring simultaneous measurements of voltage and current at the motor, applying the voltage measurement to the motor model and determining an equivalent current produced in the motor model by the applied voltage, subtracting the equivalent current from the current measurement to produce a corrected motor current, and processing the corrected motor current through motor current signature analysis. For an ac motor ( 33 ), the method includes extracting signals corresponding to the fundamental excitation frequency from the voltage measurement to produce an interfering voltage, processing the interfering voltage through the motor model to produce a corresponding spurious current signal, and subtracting the spurious current signal from the measured current to produce the corrected motor current signal for analysis.
Inventors
- 👤 Gerald Burt Kliman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:20
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/34; G01R31/343
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
90 words
A method for removing spurious signals in a process of motor current signature analysis of an electric motor ( 24 or 33 ), comprising: acquiring simultaneous measurements of voltage and current at the motor; applying the voltage measurement to a motor model ( 20 or 30 ) of the electric motor and determining an equivalent current produced in the motor model by the voltage measurement; subtracting the equivalent current from the current measurement to produce a corrected motor current; and processing the corrected motor current through motor current signature analysis.
Claim 2
Independent Claim
90 words
A method for removing spurious signals in a process of motor current signature analysis of an electric motor ( 24 or 33 ), comprising: acquiring simultaneous measurements of voltage and current at the motor; applying the voltage measurement to a motor model ( 20 or 30 ) of the electric motor and determining an equivalent current produced in the motor model by the voltage measurement; subtracting the equivalent current from the current measurement to produce a corrected motor current; and processing the corrected motor current through motor current signature analysis.
Claim 3
Dependent Claim
35 words
The method of claim 1 wherein the motor is a dc motor ( 24 ), and including removing a dc component from the voltage measurement prior to applying the voltage measurement to the motor model.
Claim 4
Dependent Claim
24 words
The method of claim 2 wherein determining the equivalent current comprises dividing the voltage measurement by a resistance (R a ) of the motor.
Claim 5
Dependent Claim
58 words
The method of claim 1 wherein the motor comprises an ac motor and the voltage measurement has a fundamental frequency, and including extracting fundamental signals corresponding to the fundamental frequency from the voltage measurement to produce an interfering voltage, wherein determining the equivalent current includes processing the interfering voltage through the motor model to produce the equivalent current.
Claim 6
Dependent Claim
27 words
The method of claim 4 wherein extracting comprises applying the voltage measurement to an analog filter ( 58 or 60 ) to remove the fundamental frequency voltage.
Claim 7
Dependent Claim
50 words
The method of claim 4 further including converting the voltage measurement to digital sampled voltage signals, and wherein extracting the fundamental signals comprises Fourier transforming the sampled voltage signals, identifying the fundamental signals from the transformed sampled voltage signals, and subtracting the identified fundamental signals from the sampled voltage signals.
Claim 8
Independent Claim
113 words
A method for removing spurious current signals from measured current at an ac electric motor ( 33 ) to enable motor current signature analysis of the measured current, the motor being excited by an applied voltage having a fundamental frequency, the method comprising: acquiring simultaneous measurements of voltage and current at the motor; removing voltage corresponding to the applied fundamental frequency voltage from the voltage measurement to yield an interfering voltage; processing the interfering voltage through a motor model corresponding to the motor to produce a spurious current signal; subtracting the spurious current signal from the current measurement to produce a corrected current; and applying the corrected current through motor current signature analysis.
Claim 9
Independent Claim
113 words
A method for removing spurious current signals from measured current at an ac electric motor ( 33 ) to enable motor current signature analysis of the measured current, the motor being excited by an applied voltage having a fundamental frequency, the method comprising: acquiring simultaneous measurements of voltage and current at the motor; removing voltage corresponding to the applied fundamental frequency voltage from the voltage measurement to yield an interfering voltage; processing the interfering voltage through a motor model corresponding to the motor to produce a spurious current signal; subtracting the spurious current signal from the current measurement to produce a corrected current; and applying the corrected current through motor current signature analysis.
Claim 10
Dependent Claim
46 words
The method of claim 7 further including converting the voltage measurement to digital sampled voltage signals, and wherein removing comprises Fourier transforming the sampled voltage signals, identifying fundamental signals from the transformed sampled voltage signals, and subtracting the identified fundamental signals from the sampled voltage signals.
Claim 11
Dependent Claim
16 words
The method of claim 8 wherein the motor model is a computer simulation of the motor.
Claim 12
Dependent Claim
37 words
The method of claim 7 wherein removing comprises applying the voltage measurement to a filter circuit ( 58 or 60 ) to extract the fundamental frequency voltage and subtract the fundamental frequency voltage from the voltage measurement.
Claim 13
Independent Claim
121 words
A system for removing spurious signals in a process of motor current signature analysis of an electric motor ( 24 or 33 ), comprising: sensors ( 32 and 34 ) for acquiring simultaneous measurements of voltage and current at the motor; and a computer ( 35 or 37 ) including: an electronic model ( 20 or 30 ) of the motor for use by the computer in determining an equivalent current produced in the motor model by the voltage measurement; a subtractor ( 29 or 52 ) for subtracting the equivalent current from the current measurement to produce a corrected motor current; and a processor ( 31 or 56 ) for processing the corrected motor current through motor current signature analysis.
Claim 14
Independent Claim
121 words
A system for removing spurious signals in a process of motor current signature analysis of an electric motor ( 24 or 33 ), comprising: sensors ( 32 and 34 ) for acquiring simultaneous measurements of voltage and current at the motor; and a computer ( 35 or 37 ) including: an electronic model ( 20 or 30 ) of the motor for use by the computer in determining an equivalent current produced in the motor model by the voltage measurement; a subtractor ( 29 or 52 ) for subtracting the equivalent current from the current measurement to produce a corrected motor current; and a processor ( 31 or 56 ) for processing the corrected motor current through motor current signature analysis.
Claim 15
Dependent Claim
66 words
The system of claim 11 wherein the motor is a dc motor ( 24 ), and wherein the computer further includes a subtractor ( 27 ) for removing a dc component of the voltage from the voltage measurement to provide a modified voltage measurement, and wherein the computer uses the modified voltage measurement in the electronic motor model ( 28 ) to determine the equivalent current.
Claim 16
Dependent Claim
27 words
The system of claim 12 wherein the computer determines the equivalent current by dividing the modified voltage measurement by a resistance (R a ) of the motor.
Claim 17
Dependent Claim
82 words
The system of claim 11 wherein the motor comprises an ac motor ( 33 ) and the voltage measurement has a fundamental frequency, and wherein the computer further includes an extractor ( 44 / 46 / 48 or 58 or 60 ) for extracting fundamental signals corresponding to the fundamental frequency from the voltage measurement to produce an interfering voltage signal, and wherein the computer uses the interfering voltage signal in the motor model ( 50 ) to produce the equivalent current.
Claim 18
Dependent Claim
17 words
The system of claim 14 wherein the extractor comprises an analog filter ( 58 or 60 ).
Claim 19
Dependent Claim
54 words
The system of claim 14 further including an analog to digital converter for converting the voltage measurement to digital sampled voltage signals, and wherein extractor is adapted to Fourier transform the sampled voltage signals, identify fundamental signals from the transformed sampled voltage signals, and subtract the identified fundamental signals from the sampled voltage signals.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-03-05 | 2004-09-04 | 2005-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-03-05 | 2008-09-04 | 2009-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-03-05 | 2012-09-04 | 2013-03-06 | $7700.00 | Window Closed / Lapsed |