Patent US4801877A successfully refreshed from Google Patents.
US4801877A
Expired / Lapsed
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Method and apparatus for testing dynamoelectric machine rotors
Assignee: General Electric Co
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Filing: 1986-05-06
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Granted: 1989-01-31
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Expires: 2006-05-06
Abstract
Abstract A method and apparatus for testing dynamoelectric machine rotors, particularly squirrel cage rotors for induction motors, to obtain resistance, reactance, and effective skew values to permit identification of rotor defects. The rotor is rotated in an alternating magnetic field and pick-up coils are used to sense the voltage generated in the rotor by sensing the magnetic flux generated by magnetization of the rotor during rotation. Current sensing is used to determine the current used in magnetizing the rotor and a separate skew pick-up coil is utilized to detect effective electrical skew. These signals are processed to determine whether the rotor meets predetermined pass/fail criteria, to provide detailed statistical data and to generate a failure indication responsive to one of the values falling outside respective predetermined limits.
Inventors
- 👤 Phillip R. Herrick
- 👤 Daniel C. Ewing
- 👤 Floyd H. Wright
- 👤 Kevin M. Truelove
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:27
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/34; G01R31/346
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
108 words
Test apparatus for testing dynamoelectric machine rotors, comprising: a test fixture including means for accepting and imparting angular movement to a rotor, exciting means for magnetizing the rotor during said angular movement in response to an alternating current applied thereto; voltage sensing means for generating a voltage signal in response to magnetic flux generated by the rotor; current sensing means for sensing the magnitude of the alternating current utilized to magnetize the rotor and for generating a current signal corresponding thereto; and signal processing means for determining at least one of resistance and reactance values of the rotor in response to both the voltage signal and current signal.
Claim 2
Dependent Claim
108 words
Test apparatus for testing dynamoelectric machine rotors, comprising: a test fixture including means for accepting and imparting angular movement to a rotor, exciting means for magnetizing the rotor during said angular movement in response to an alternating current applied thereto; voltage sensing means for generating a voltage signal in response to magnetic flux generated by the rotor; current sensing means for sensing the magnitude of the alternating current utilized to magnetize the rotor and for generating a current signal corresponding thereto; and signal processing means for determining at least one of resistance and reactance values of the rotor in response to both the voltage signal and current signal.
Claim 3
Dependent Claim
50 words
The test apparatus of claim 1 further comprising skew sensing means for sensing the effective electrical skew of the rotor and for generating an effective skew signal responsive thereto, and wherein the signal processing means determines an effective electrical skew of the rotor in response to the effective skew signal.
Claim 4
Dependent Claim
34 words
The test apparatus of claim 2 wherein the signal processing means comprises a synchronous data sampling means for simultaneously sampling the current signal and the voltage signal in synchronization with the applied alternating current.
Claim 5
Dependent Claim
33 words
The test apparatus of claim 3 wherein the sampling means further comprises a phase locked loop for generating synchronization pulses synchronized to the alternating current to synchronize the sampling with the alternating current.
Claim 6
Dependent Claim
27 words
The test apparatus of claim 4 wherein the sampling means further comprises a sample and hold circuit for simultaneously sampling the current signal and the voltage signal.
Claim 7
Dependent Claim
30 words
The test apparatus of claim 5 wherein the sampling means comprises analog to digital conversion means for converting the signals sampled by the sample and hold means to digital data.
Claim 8
Dependent Claim
32 words
The test apparatus of claim 6 wherein the signal processing means further comprises computer means for processing the digital data to determine calculated values including the resistance and reactance of the rotor.
Claim 9
Dependent Claim
24 words
The test apparatus of claim 7 wherein the computer means processes the digital data to determine a calculated effective skew value of the rotor.
Claim 10
Dependent Claim
22 words
The test apparatus of claim 8 wherein the computer means processes the digital data to determine calculate dissymmetry and skew dissymmetry values.
Claim 11
Dependent Claim
51 words
The test apparatus of claim 9 wherein the computer means comprises a multi-computer system having a first computer for controlling the sample means and for performing initial digital data processing to produce partially processed data, and a second computer for further processing the partially processed data and for generating control signals.
Claim 12
Dependent Claim
59 words
The test apparatus of claim 9 wherein the computer means further comprises means for comparing at least one of the resistance, reactance, effective skew, dissymmetry and skew dissymmetry values to respective predetermined maximum or minimum threshold values and for generating a failure indication in response to one of the values exceeding or being less than its respective maximum threshold.
Claim 13
Dependent Claim
26 words
The test apparatus of claim 6 wherein the signal processing means further comprises display means for displaying calculated values, and printing means for printing calculated values.
Claim 14
Dependent Claim
34 words
The test apparatus of claim 1 wherein the test fixture comprises a plurality of test heads each comprising means for accepting and rotating a rotor and exciting means for magnetizing the rotor during rotation.
Claim 15
Dependent Claim
64 words
The test apparatus of claim 1 wherein the test fixture means comprises rotor clutch means for creating a substantially slip free contact with the rotor, and means for retracting the rotor into a test head, and drive means for rotating the rotor within the test head for a predetermined amount of rotations at a predetermined rate in response to activation of a start switch.
Claim 16
Dependent Claim
51 words
The test apparatus of claim 14 wherein the rotor clutch means comprises a spindle having at least one compressible o-ring for axially receiving the rotor, and an hydraulically activated compression means for compressing the o-ring to cause the o-ring to expand radially against the rotor to thereby form a gripping contact.
Claim 17
Dependent Claim
55 words
The test apparatus of claim 1 wherein the signal processing means comprises analog to digital conversion means for digitizing the voltage and current signals to provide digital voltage and current signals, and digital processing means for digital processing of the digital voltage and current signals to determine calculated resistance and reactance values for the rotor.
Claim 18
Dependent Claim
54 words
The test apparatus of claim 16 further comprising skew sensing means for sensing the effective electrical skew of the rotor and for generating an effective skew signal responsive thereto and wherein the signal processing means digitizes the effective skew signal and determines a calculated skew value in response to the digitized effective skew signal.
Claim 19
Dependent Claim
34 words
The test apparatus of claim 16 wherein the signal processing means comprises a synchronous data sampling means for simultaneously sampling the current signal and the voltage signal in synchronization with the applied alternating current.
Claim 20
Dependent Claim
94 words
Test apparatus for testing dynamoelectric machine rotors, comprising: a test fixture including means for accepting a rotor and imparting angular movement to the rotor, exciting means for magnetizing the rotor during said angular movement utilizing an alternating current applied thereto; sensing means for sensing at least one characteristic related to at least one selected electrical characteristic of the rotor and for generating sense signals in response thereto; and signal processing means for calculating and storing a value of at least one selected electrical characteristic of the rotor automatically in response to the sense signals.
Claim 21
Dependent Claim
94 words
Test apparatus for testing dynamoelectric machine rotors, comprising: a test fixture including means for accepting a rotor and imparting angular movement to the rotor, exciting means for magnetizing the rotor during said angular movement utilizing an alternating current applied thereto; sensing means for sensing at least one characteristic related to at least one selected electrical characteristic of the rotor and for generating sense signals in response thereto; and signal processing means for calculating and storing a value of at least one selected electrical characteristic of the rotor automatically in response to the sense signals.
Claim 22
Dependent Claim
52 words
The test apparatus of claim 19 wherein the signal processing means comprises digital conversion means for digitizing the sense signals to provide digital sense signals and digital processing means for digital processing of the digital sense signals to determine a calculated value for at least one selected electrical characteristic of the rotor.
Claim 23
Dependent Claim
50 words
The test apparatus of claim 19 wherein the sense means senses a plurality of different selected electrical characteristics and generates a plurality of sense signals and wherein the processing means determines values of a plurality of different electrical characteristics of the rotor in response to the plurality of sense signals.
Claim 24
Dependent Claim
150 words
Test apparatus for testing dynamoelectric machine rotors, comprising: a test fixture including means for accepting and imparting angular movement to a rotor, exciting means for magnetizing the rotor during said angular movement utilizing an alternating current applied thereto; sensing apparatus selected from the group consisting of (1) sensing means for generating a voltage signal in response to magnetic flux generated by the rotor and for sensing the magnitude of the alternating current utilized to magnetize the rotor including means for determining at least one of resistance and reactance values of the rotor in response to the voltage signal and the magnitude of the alternating current, and (2) sensing means for sensing an effective electrical skew of the rotor and for generating an effective skew signal in response thereto, including means for determining a value of the effective electrical skew of the rotor automatically in response to the effective skew signal.
Claim 25
Dependent Claim
150 words
Test apparatus for testing dynamoelectric machine rotors, comprising: a test fixture including means for accepting and imparting angular movement to a rotor, exciting means for magnetizing the rotor during said angular movement utilizing an alternating current applied thereto; sensing apparatus selected from the group consisting of (1) sensing means for generating a voltage signal in response to magnetic flux generated by the rotor and for sensing the magnitude of the alternating current utilized to magnetize the rotor including means for determining at least one of resistance and reactance values of the rotor in response to the voltage signal and the magnitude of the alternating current, and (2) sensing means for sensing an effective electrical skew of the rotor and for generating an effective skew signal in response thereto, including means for determining a value of the effective electrical skew of the rotor automatically in response to the effective skew signal.
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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) | 1992-01-31 | 1992-08-01 | 1993-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-31 | 1996-08-01 | 1997-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-31 | 2000-08-01 | 2001-01-31 | $7700.00 | Window Closed / Lapsed |