US4583146A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fault current interrupter
Assignee: General Electric Co
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Filing: 1984-10-29
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Granted: 1986-04-15
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Expires: 2004-10-29
Abstract
Abstract A fault current interrupter is provided by the parallel combination of a positive temperature coefficient resistor and a voltage dependent resistor connected across a pair of separable contacts to permit the interruption of current without the occurrence of arcing between the contacts when the contacts first become separated. The positive temperature coefficient resistor is selected to have a relatively low resistance at room temperature and a substantially higher resistance at higher temperatures. This allows the current to transfer away from the contacts through the positive temperature coefficient resistor until the voltage across the voltage dependent resistor causes the voltage dependent resistor to become conductive and thereby transfer the current away from the positive temperature coefficient resistor.
Inventors
- 👤 Edward K. Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:26
CPC Classifications
H; H01; H01H; H01H33/00; H01H33/02; H01H33/04; H01H33/16; H01H33/161; H01H9/00; H01H9/30; H01H9/42; H01H2033/163
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
80 words
A fault current interrupter comprising: a pair of separable electric contacts arranged for interrupting current flow through an electric circuit; and a positive temperature coefficient resistor electrically connected in parallel across said electric contacts for transferring said current through said positive temperature coefficient resistor when said electric contacts first become separated, said positive temperature coefficient resistor including a layer of material having voltage dependent properties to increase the rate at which said positive temperature coefficient material reached a predetermined temperature.
Claim 2
Dependent Claim
80 words
A fault current interrupter comprising: a pair of separable electric contacts arranged for interrupting current flow through an electric circuit; and a positive temperature coefficient resistor electrically connected in parallel across said electric contacts for transferring said current through said positive temperature coefficient resistor when said electric contacts first become separated, said positive temperature coefficient resistor including a layer of material having voltage dependent properties to increase the rate at which said positive temperature coefficient material reached a predetermined temperature.
Claim 3
Dependent Claim
89 words
A fault current interrupter comprising: a pair of separable electric contacts arranged for interrupting current flow through an electric circuit; and a positive temperature coefficient resistor electrically connected in parallel across said electric contacts for transferring said current through said positive temperature coefficient resistor when said electric contacts first become separated, said positive temperature coefficient resistor comprising a material having grain boundaries and wherein said grain boundaries include a material having voltage dependent properties to increase the rate at which said positive temperature coefficient material reaches a predetermined temperature.
Claim 4
Dependent Claim
89 words
A fault current interrupter comprising: a pair of separable electric contacts arranged for interrupting current flow through an electric circuit; and a positive temperature coefficient resistor electrically connected in parallel across said electric contacts for transferring said current through said positive temperature coefficient resistor when said electric contacts first become separated, said positive temperature coefficient resistor comprising a material having grain boundaries and wherein said grain boundaries include a material having voltage dependent properties to increase the rate at which said positive temperature coefficient material reaches a predetermined temperature.
Claim 5
Dependent Claim
86 words
A fault current interrupter comprising: a pair of contacts and a resistor connected across said contacts; said resistor comprising a composite material having a positive temperature coefficient of resistance whereby said resistor exhibits a first resistance at a first temperature and a second higher resistance at a second higher temperature, said material also having voltage dependent properties whereby said resistor exhibits a third resistance at a first voltage drop across said resistor and a fourth lower resistance at a second higher voltage drop across said resistor.
Claim 6
Dependent Claim
86 words
A fault current interrupter comprising: a pair of contacts and a resistor connected across said contacts; said resistor comprising a composite material having a positive temperature coefficient of resistance whereby said resistor exhibits a first resistance at a first temperature and a second higher resistance at a second higher temperature, said material also having voltage dependent properties whereby said resistor exhibits a third resistance at a first voltage drop across said resistor and a fourth lower resistance at a second higher voltage drop across said resistor.
Claim 7
Dependent Claim
63 words
The fault current interrupter of claim 3 wherein said positive temperature coefficient resistor and said voltage dependent resistor comprises a composite material whereby said current transfers through one component of said composite material at a first temperature when said electric contacts first becomes separated and then transfers through another component of said composite material at a second temperature higher than said first temperature.
Claim 8
Dependent Claim
31 words
The fault current interrupter of claim 3 wherein said composite material comprises a first material having said positive temperature coefficient of resistance and a second material having said voltage dependent properties.
References Cited (Backward Citations)
US3249810A
Cited
US3962145A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |