US4704906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dynamic air gap measuring device for use with rotating electrical machinery
Assignee: Electric Power Research Institute
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Filing: 1986-04-10
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Granted: 1987-11-10
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Expires: 2006-04-10
Abstract
Abstract The air gap between a rotor and a stator in rotating electrical machinery is determined using sonar techniques. An ultrasonic signal transmitter and receiver are mounted on one of the rotor and stator for transmitting ultrasonic signals to the other of the rotor and stator and receiving reflections therefrom. The time between signal transmission and reflected signal reception is determined, and the spacing of the rotor and stator is determined from the time, the velocity of sound, and the speed of rotation of the rotor.
Inventors
- 👤 Thomas L. Churchill
- 👤 James M. Ross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:42
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/88; G01S15/02; G01S15/06; G01S15/08; G01S15/10; G01S15/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
108 words
Apparatus for measuring air gap between a rotor and a stator in rotating electrical machinery comprising ultrasound signal transmitter means for transmitting a pulsed signal, ultrasound signal receiver means for receiving a pulsed echo signal and generating an electrical receiver signal in response thereto, means for mounting said signal transmitter means and said signal receiver means on one of said rotor and stator whereby signals can be transmitted to the other of said rotor and stator and reflected back to said signal receiver means, and means for determining the time between signal transmission and echo signal reception and determining the air gap between the rotor and said stator.
Claim 2
Dependent Claim
108 words
Apparatus for measuring air gap between a rotor and a stator in rotating electrical machinery comprising ultrasound signal transmitter means for transmitting a pulsed signal, ultrasound signal receiver means for receiving a pulsed echo signal and generating an electrical receiver signal in response thereto, means for mounting said signal transmitter means and said signal receiver means on one of said rotor and stator whereby signals can be transmitted to the other of said rotor and stator and reflected back to said signal receiver means, and means for determining the time between signal transmission and echo signal reception and determining the air gap between the rotor and said stator.
Claim 3
Dependent Claim
26 words
Apparatus as defined by claim 1 wherein said signal transmitter means comprises a first ultrasonic transducer and said signal receiver means comprises a second ultrasonic transucer.
Claim 4
Dependent Claim
21 words
Apparatus as defined by claim 1 wherein said signal transmitter means and said signal receiver means comprise a single ultrasonic transducer.
Claim 5
Dependent Claim
65 words
Apparatus as defined by claim 1 wherein said signal transmitter means includes timing means for controlling the transmission of signals and generating a start pulse, driver means responsive to said timing means for applying driving signal to said signal transmitter means, amplifier means for receiving and amplifying said electrical receiver signal, and a discriminator responsive to said electrical receiver signal and generating a stop pulse.
Claim 6
Dependent Claim
15 words
Apparatus as defined by claim 4 wherein said discriminator comprises a level sensitive pulse detector.
Claim 7
Dependent Claim
30 words
Apparatus as defined by claim 1 wherein said means for determining the air gap includes a computer and further including telemetry means for transmitting signals to and from said computer.
Claim 8
Dependent Claim
42 words
Apparatus as defined by claim 6 and further including a plurality of signal transmitter means and signal receiver means mounted in spaced relationship and further including multiplexer means for selecting one of said plurality of signal transmission means and signal receiver means.
Claim 9
Independent Claim
72 words
A method of measuring air gap between a rotor and a stator in rotating electrical machinery comprising the steps of mounting signal transmitter and receiver means on one of said rotor and stator, transmitting signals to the other of said rotor and stator and receiving reflected signals therefrom, determining the time between signal transmission and reflected signal reception, and determining from said time the air gap between said rotor and said stator.
Claim 10
Independent Claim
72 words
A method of measuring air gap between a rotor and a stator in rotating electrical machinery comprising the steps of mounting signal transmitter and receiver means on one of said rotor and stator, transmitting signals to the other of said rotor and stator and receiving reflected signals therefrom, determining the time between signal transmission and reflected signal reception, and determining from said time the air gap between said rotor and said stator.
Claim 11
Dependent Claim
33 words
The method as defined by claim 8 wherein said step of mounting signal transmitter and receiver means includes mounting a plurality of transmitter and receiver means about one of said stator and rotor.
Claim 12
Dependent Claim
25 words
The method as defined by claim 9 and further including the step of periodically activating each of said plurality of signal transmitter and receiver means.
References Cited (Backward Citations)
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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) | 1990-11-09 | 1991-05-11 | 1991-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-09 | 1995-05-11 | 1995-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-09 | 1999-05-11 | 1999-11-10 | $7700.00 | Window Closed / Lapsed |