US4737775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Insulation deterioration monitoring apparatus
Assignee: Meidensha Corp
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Filing: 1985-12-09
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Granted: 1988-04-12
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Expires: 2005-12-09
Abstract
Abstract The apparatus for monitoring an insulation deterioration of an insulation layer surrounding an outer surface of a coil conductor comprises a semiconductor layer of 10 2 to 10 7 ohm-cm formed within the insulation layer of the coil, an electric field sensor such as Pockels element or ferroelectric element mounted on the coil insulation layer. The semiconductor layer is so formed as to divide the insulation layer into inner and outer layers. When the inner layer deteriorates, a high electric field is sensed, while the outer layer deteriorates, a low electric field is sensed. Therefore, it is possible to discriminate the insulation deterioration positions on the basis of the change in electric field detected by the sensor element. In case of deterioration, alarms are produced or the power supply of machine is turned off for safety.
Inventors
- 👤 Takao Tokuda
- 👤 Hisashi Suwahara
- 👤 Yasuaki Nozu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:29
CPC Classifications
G; G01; G01R; G01R1/00; G01R31/00; G01R31/34; G01R31/346; G01R15/00; G01R15/14; G01R15/24; G01R15/241; G01R15/242
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
134 words
An apparatus for use with an electric coil placed in an iron core, the electric coil having a coil conductor and an electric insulator surrounding the coil conductor to provide a predetermined degree of electric insulation between the coil conductor and the iron core, comprising: (a) a semiconductor layer provided at least in a portion of the electric insulator to divided the electric insulator portion into outer and inner layers and; (b) a sensor provided on the coil, the sensor being sensitive to an electric field existing therearound for producing a sensor signal indicative of a sensed electric field intensity when a voltage is applied between the coil conductor and the iron core; and (c) a detector responsive to the sensor signal for detecting a deterioration of the electric insulation of the electric insulator.
Claim 2
Independent Claim
134 words
An apparatus for use with an electric coil placed in an iron core, the electric coil having a coil conductor and an electric insulator surrounding the coil conductor to provide a predetermined degree of electric insulation between the coil conductor and the iron core, comprising: (a) a semiconductor layer provided at least in a portion of the electric insulator to divided the electric insulator portion into outer and inner layers and; (b) a sensor provided on the coil, the sensor being sensitive to an electric field existing therearound for producing a sensor signal indicative of a sensed electric field intensity when a voltage is applied between the coil conductor and the iron core; and (c) a detector responsive to the sensor signal for detecting a deterioration of the electric insulation of the electric insulator.
Claim 3
Dependent Claim
23 words
The apparatus as claimed in claim 1, wherein the semiconductor layer has a resistance value ranging from 10 2 to 10 7 ohm-cm.
Claim 4
Dependent Claim
79 words
The apparatus as claimed in claim 1, wherein the detector includes means for setting a predetermined range defined by upper and lower limits, means for providing an indication of an electric insulation deterioration of the electric insulator upper layer when the sensor signal has a level smaller than the lower limit, means for providing an indication of an electric insulation deterioration of the electric insulator lower layer when the sensor signal has a level greater than the upper limit.
Claim 5
Dependent Claim
28 words
The apparatus as claimed in claim 3, wherein the detector includes means for providing an alarm when the sensor signal has a level out of the predetermined range.
Claim 6
Dependent Claim
39 words
The apparatus as claimed in claim 3, wherein the detector includes means for terminating the application of the voltage between the coil conductor and the iron core when the sensor signal has a level out of the predetermined range.
Claim 7
Dependent Claim
28 words
The apparatus as claimed in claim 1, wherein the sensor includes a Pockels electric field sensor for producing an optical signal indicative of the sensed electric field intensity.
Claim 8
Dependent Claim
87 words
The apparatus as claimed in claim 6, wherein the Pockels electric field sensor includes a light source for emitting a light, a Pockels element having a bismuth silicon oxide element sandwiched between first and second electrodes for sensing an electric field, the Pockels element optically connected to the light source for modulating the light to an optical phase difference corresponding to the intensity of the sensed electric field applied between the first and second electrodes, and means for converting the optical phase difference into the sensor signal.
Claim 9
Dependent Claim
23 words
The apparatus as claimed in claim 7, wherein the first electrode is grounded and the second electrode is placed on the electric insulator.
Claim 10
Dependent Claim
27 words
The apparatus as claimed in claim 7, wherein the first electrode is grounded and the second electrode is placed through an insulating member on the electric insulator.
Claim 11
Dependent Claim
23 words
The apparatus as claimed in claim 7, wherein the first electrode is connected to the iron core and the second electrode is free.
Claim 12
Dependent Claim
23 words
The apparatus as claimed in claim 7, wherein the first electrode is connected to the coil conductor and the second electrode is free.
Claim 13
Dependent Claim
27 words
The apparatus as claimed in claim 7, wherein the first electrode is connected to the coil conductor and the second electrode is connected to the semiconductor layer.
Claim 14
Dependent Claim
36 words
The apparatus as claimed in claim 7, wherein the first electrode is grounded and the second electrode is connected to a conductive strip wound around the electric insulator at a position facing to the semiconductor layer.
Claim 15
Dependent Claim
35 words
The apparatus as claimed in claim 7, wherein the first electrode is free and the second electrode is connected to a conductive strip wound around the electric insulator at a position surrounding the semiconductor layer.
Claim 16
Dependent Claim
35 words
The apparatus as claimed in claim 7, wherein the first electrode is free and the second electrode is connected to a conductive strip wound around the electric insulator at a position surrounding the semiconductor layer.
Claim 17
Dependent Claim
36 words
The apparatus as claimed in claim 7, wherein the first electrode is connected to an insulated electric wire wound around the electric insulator at a position surrounding the semiconductor layer and the second electrode is grounded.
Claim 18
Dependent Claim
36 words
The apparatus as claimed in claim 7, wherein the first electrode is connected to an insulated electric wire wound around the electric insulator at a position surrounding the semiconductor layer and the second electrode is free.
Claim 19
Dependent Claim
26 words
The apparatus as claimed in claim 1, wherein the sensor includes a ferroelectric element for producing a sensor signal indicative of the sensed electric field intensity.
Claim 20
Dependent Claim
79 words
The apparatus as claimed in claim 18, wherein the detector includes means for setting a predetermined range defined by upper and lower limits, means for providing an indication of an electric insulation deterioration of the electric insulator upper layer when the sensor signal has a level smaller than the lower limit, means for providing an indication of an electric insulation deterioration of the electric insulator lower layer when the sensor signal has a level greater than the upper limit.
Claim 21
Dependent Claim
28 words
The apparatus as claimed in claim 19, wherein the detector includes means for providing an alarm when the sensor signal has a level out of the predetermined range.
Claim 22
Dependent Claim
39 words
The apparatus as claimed in claim 19, wherein the detector includes means for terminating the application of the voltage between the coil conductor and the iron core when the sensor signal has a level out of the predetermined range.
Claim 23
Dependent Claim
19 words
The apparatus as claimed in claim 19, wherein the ferroelectric element is mounted on the electric insulator outer layer.
Claim 24
Dependent Claim
22 words
The apparatus as claimed in claim 19, wherein the ferroelectric element is mounted through an insulator on the electric insulator outer layer.
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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) | 1991-04-12 | 1991-10-12 | 1992-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-12 | 1995-10-12 | 1996-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-12 | 1999-10-12 | 2000-04-12 | $7700.00 | Window Closed / Lapsed |