US3172012A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective relay for polyphase machines responsive solely to positive and negative sequence currents
Assignee: Individual
•
Filing: 1960-02-04
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Granted: 1965-03-02
•
Expires: 1980-02-04
Abstract
No abstract record available.
Inventors
- 👤 Burns N Gafford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:54
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/34; H02H3/343; H01; H01H; H01H53/00; H01H53/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
142 words
A PROTECTIVE SYSTEM FOR POLYPHASE MACHINES HAVING A HEATING CHARACTERISTIC SUCH THAT THE HEATING EFFECT OF NEGATIVE-SEQUENCE CURRENTS, I2 IS GREATER THAN THAT OF POSITIVE-SEQUENCE CURRENTS, I1 COMPRISING A TORQUE RESPONSIVE MEANS, A TORQUE PRODUCING MEANS COACTING WITH THE TORQUE RESPONSIVE MEANS TO APPLY A TORQUE THERETO SOLELY PROPORTIONAL TO I12, A TORQUE PRODUCING MEANS COACTING WITH THE TORQUE RESPONSIVE MEANS TO APPLY A TORQUE THERETO SOLELY PROPORTIONAL TO KI22 WHERE K HAS A VALUE SUBSTANTIALLY GREATER THAN 1, WHEREBY THE TORQUE RESPONSIVE MEANS HAS A TORQUE APPLIED THERETO PROPORTIONAL TO I12+KI22, THE AFORESAID TORQUE PRODUCING MEANS BEING THE ONLY MEANS RESPONSIVE TO AN ELECTRICAL CONDITION IN THE MACHINE BEING PROTECTED, AND MEANS RESPONSIVE TO PREDETERMINED ACTUATION OF THE TORQUE RESPONSIVE MEANS BY THE TORQUE PRODUCING MEANS INDICATIVE OF A PREDETERMINED TEMPERATURE RISE TO PROVIDE PROTECTION OF THE POLYPHASE MACHINE FROM OVERHEATING.
Claim 2
Dependent Claim
142 words
A PROTECTIVE SYSTEM FOR POLYPHASE MACHINES HAVING A HEATING CHARACTERISTIC SUCH THAT THE HEATING EFFECT OF NEGATIVE-SEQUENCE CURRENTS, I2 IS GREATER THAN THAT OF POSITIVE-SEQUENCE CURRENTS, I1 COMPRISING A TORQUE RESPONSIVE MEANS, A TORQUE PRODUCING MEANS COACTING WITH THE TORQUE RESPONSIVE MEANS TO APPLY A TORQUE THERETO SOLELY PROPORTIONAL TO I12, A TORQUE PRODUCING MEANS COACTING WITH THE TORQUE RESPONSIVE MEANS TO APPLY A TORQUE THERETO SOLELY PROPORTIONAL TO KI22 WHERE K HAS A VALUE SUBSTANTIALLY GREATER THAN 1, WHEREBY THE TORQUE RESPONSIVE MEANS HAS A TORQUE APPLIED THERETO PROPORTIONAL TO I12+KI22, THE AFORESAID TORQUE PRODUCING MEANS BEING THE ONLY MEANS RESPONSIVE TO AN ELECTRICAL CONDITION IN THE MACHINE BEING PROTECTED, AND MEANS RESPONSIVE TO PREDETERMINED ACTUATION OF THE TORQUE RESPONSIVE MEANS BY THE TORQUE PRODUCING MEANS INDICATIVE OF A PREDETERMINED TEMPERATURE RISE TO PROVIDE PROTECTION OF THE POLYPHASE MACHINE FROM OVERHEATING.
References Cited (Backward Citations)
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US1726928A
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US1816772A
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US1816779A
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US1939044A
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US2231717A
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US2836767A
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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) | 1968-03-01 | 1968-08-31 | 1969-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-03-01 | 1972-08-31 | 1973-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-03-01 | 1976-08-31 | 1977-03-02 | $7700.00 | Window Closed / Lapsed |