US4397775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Varistors with controllable voltage versus time response
Assignee: Hubbell Inc
•
Filing: 1981-06-01
•
Granted: 1983-08-09
•
Expires: 2001-06-01
Abstract
Abstract A bismuth-free, zinc oxide based varistor exhibits a controllable overshoot/undershoot voltage characteristic. The varistor is composed of zinc oxide as the primary constituent, with smaller quantities of barium, boron, one or more transition elements and aluminum. Varistor voltage versus time response is dependent on the degree of aluminum doping. Typically, more than approximately 0.003 mole percent, but less than approximately 0.1 mole percent aluminum is employed, depending on desired voltage overshoot/undershoot characteristic.
Inventors
- 👤 Lionel M. Levinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:43
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/112
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
58 words
A sintered ceramic, bismuth-free metal oxide varistor composition consisting essentially of between about 70 and 99.5 mole percent ZnO as a primary constituent, and finite quantities of additive oxides of barium, boron, aluminum, and at least one additive transition element oxide, said finite additive quantities in aggregate comprising between about 0.5 and 30 mole percent of said composition.
Claim 2
Dependent Claim
58 words
A sintered ceramic, bismuth-free metal oxide varistor composition consisting essentially of between about 70 and 99.5 mole percent ZnO as a primary constituent, and finite quantities of additive oxides of barium, boron, aluminum, and at least one additive transition element oxide, said finite additive quantities in aggregate comprising between about 0.5 and 30 mole percent of said composition.
Claim 3
Dependent Claim
34 words
The varistor of claim 1 wherein said barium additive is provided in a presintered varistor powder by addition to said powder of at least one of the group consisting of BaCO 3 and BaO.
Claim 4
Dependent Claim
40 words
The varistor of claim 2 wherein said boron additive is provided in said presintered varistor powder by addition to said powder of at least one of the group consisting of H 3 BO 3 and B 2 O 3 .
Claim 5
Dependent Claim
29 words
The varistor of claim 3 wherein said transition element additive comprises at least one of the group consisting of NiO, Co 2 O 3 , and Mn 2 O.
Claim 6
Dependent Claim
41 words
The varistor of claim 4 wherein said aluminum additive is provided in said presintered powder by addition to said powder of at least one of the group consisting of Al 2 (CO 3 ) 3 and Al(NO 3 ) 3 .
Claim 7
Dependent Claim
29 words
The varistor as in any of preceding claims 2, 3, 4, or 5 wherein said aluminum additive to said powder comprises between 0.003 mole percent and 0.1 mole percent.
Claim 8
Dependent Claim
27 words
The varistor as in any of preceding claims 2, 3, 4, or 5 wherein said aluminum additive to said powder comprises between 0.01 and 0.03 mole percent.
Claim 9
Dependent Claim
53 words
A varistor made from a sintered mixture consisting essentially of 0.5 mole percent of each of BaCO 3 , NiO, Co 2 O 3 , and MnO 2 , 1 mole percent H 3 BO 3 , and between 0.003 and 0.1 mole percent Al(NO 3 ) 3 , the balance being ZnO.
Claim 10
Dependent Claim
53 words
A varistor made from a sintered mixture consisting essentially of 0.5 mole percent of each of BaCO 3 , NiO, Co 2 O 3 , and MnO 2 , 1 mole percent H 3 BO 3 , and between 0.003 and 0.1 mole percent Al(NO 3 ) 3 , the balance being ZnO.
Claim 11
Dependent Claim
29 words
The varistor of claim 8 in which Al(NO 3 ) 3 is present in an amount between 0.01 mole percent and 0.03 mole percent , the balance being ZnO.
References Cited (Backward Citations)
USRE29731E
Cited
US3999159A
Cited
US4094061A
Cited
US4127511A
Cited
US4184984A
Cited
US4169071A
Cited
US4285839A
Cited
US4296002A
Cited
US4297250A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-08 | 1987-02-07 | 1987-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-08 | 1991-02-07 | 1991-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-08 | 1995-02-07 | 1995-08-09 | $7700.00 | Window Closed / Lapsed |