US4219518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving varistor upturn characteristics
Assignee: General Electric Co
•
Filing: 1978-05-15
•
Granted: 1980-08-26
•
Expires: 1998-05-15
Abstract
Abstract A method for producing varistors exhibiting improved upturn characteristics comprises controllably heating a pressed varistor powder mix to a temperature, and for a time, sufficient to form a ceramic material, and then quenching the ceramic material at a rate in excess of approximately 500° C. per hour. The method is particularly advantageous when dopants such as aluminum, antimony, indium, and gallium are employed. Additionally, a surge arrester is disclosed comprising a varistor connected in series with a spark gap, the varistor being produced in accordance with the aforementioned quenching method.
Inventors
- 👤 Herbert R. Philipp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:50
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/112; H01C17/00; H01C17/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
58 words
A method for producing metal oxide varistors exhibiting improved upturn characteristics comprising: controllably heating a pressed varistor powder mix to a temperature between approximately 900° C. and 1,500° C. for a time sufficient to form a ceramic material; and controllably quenching said ceramic material at a rate in excess of approximately 500° C. to 3,000° C. per hour.
Claim 2
Independent Claim
58 words
A method for producing metal oxide varistors exhibiting improved upturn characteristics comprising: controllably heating a pressed varistor powder mix to a temperature between approximately 900° C. and 1,500° C. for a time sufficient to form a ceramic material; and controllably quenching said ceramic material at a rate in excess of approximately 500° C. to 3,000° C. per hour.
Claim 3
Dependent Claim
26 words
The method of claim 1 in which the varistor powder mix is doped with material selected from the group consisting of aluminum, antimony, indium, and gallium.
Claim 4
Dependent Claim
24 words
The method of claim 2 in which the dopant level is between approximately 0.1 parts per million atomic and 1,000 parts per million atomic.
Claim 5
Dependent Claim
22 words
The method of claim 1 in which the varistor powder mix contains additives selected from the group consisting of barium and boron.
Claim 6
Dependent Claim
24 words
The method of claim 4 in which the additives comprise between approximately 0.1 mole percent and 10 mole percent of said varistor powder mix.
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) | 1983-08-26 | 1984-02-25 | 1984-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-26 | 1988-02-25 | 1988-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-26 | 1992-02-25 | 1992-08-26 | $7700.00 | Window Closed / Lapsed |