US3842318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shielded metal enclosed electrical equipment
Assignee: ABB Inc USA
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Filing: 1973-06-19
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Granted: 1974-10-15
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Expires: 1993-06-19
Abstract
Abstract A high voltage electrical device, such as a lightning arrester, enclosed in a grounded metal enclosure filled with a pressurized dielectric gas. The device is provided with an asymmetrical shield and grading means to control the voltage distribution across the device.
Inventors
- 👤 T Nitta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:09
CPC Classifications
H; H01; H01T; H01T4/00; H01T4/16; H01T4/20; H02; H02B; H02B13/00; H02B13/02; H02B13/035; H02B13/075
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
64 words
In combination, a grounded metal enclosure, an electrical device enclosed in said enclosure and adapted to have a high voltage applied thereto, said enclosure containing an insulating gas, an asymmetrical conducting shield at least partially surrounding said device to control the voltage distribution to ground across the device, and means encircling the device inside said shield to maintain a symmetrical field within the device.
Claim 2
Dependent Claim
64 words
In combination, a grounded metal enclosure, an electrical device enclosed in said enclosure and adapted to have a high voltage applied thereto, said enclosure containing an insulating gas, an asymmetrical conducting shield at least partially surrounding said device to control the voltage distribution to ground across the device, and means encircling the device inside said shield to maintain a symmetrical field within the device.
Claim 3
Dependent Claim
30 words
The combination of claim 1 in which said shield extends from one end of the electrical device toward the other and progressively decreases in circumferential extent toward said other end.
Claim 4
Dependent Claim
32 words
The combination of claim 1 in which the last-mentioned means comprises a series of conductive rings spaced from each other and extending from one end of said electrical device to the other.
Claim 5
Dependent Claim
41 words
The combination of claim 3 in which said shield extends from one end of the electrical device toward the other end with decreasing circumferential extent such that the capacitance between the shield and said rings progressively decreases toward said other end.
Claim 6
Dependent Claim
41 words
The combination of claim 3 in which said shield is a cylindrical member encircling the electrical device at one end thereof and extending toward the other end, said cylindrical member terminating on a plane inclined to the axis of the device.
Claim 7
Dependent Claim
33 words
The combination of claim 5 in which the electrical device is a lightning arrester having a line terminal and a ground terminal, and the shield is in electrical contact with the line terminal.
Claim 8
Dependent Claim
29 words
The combination of claim 5 in which the electrical device is a conductor extending through an insulating bushing, and the shield encircles the bushing at the ground end thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |