Patent US3617807A successfully refreshed from Google Patents.
US3617807A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current-limiting switch employing low-temperature resistor
Assignee: Siemens AG
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Filing: 1970-05-20
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Granted: 1971-11-02
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Expires: 1990-05-20
Abstract
Abstract A circuit interrupter is provided with a parallel-connected resistor which is cooled to a temperature of from 4* K. to 80* K., but higher than the critical temperature of the resistance material. The resistor is connected in parallel with the circuit interrupter contacts at either an arbitrary time or just prior to a current zero value. The heating of the resistor during currentlimiting operation increases its resistivity by about 100 times.
Inventors
- 👤 Fritz Kesselring
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:19
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/02; H02H3/021; H01; H01H; H01H33/00; H01H33/002; H01H33/004; H01H33/02; H01H33/04; H01H33/16; H01H33/161; H01H33/28; H01H33/285; H02H9/00; H02H9/02; H01H2033/163
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
119 words
An arc interrupting device for an electrical circuit comprising at least one main switch and at least one resistor electrically connectable in parallel circuit therewith whose resistance increases with temperature and to which current flowing through said main switch is shifted upon the opening of said switch, characterized by means being present to cool said resistor under normal operating conditions to a temperature between 4* K. and 80* K. and higher than the critical temperature of the material from which said resistor is constructed, and that as said circuit resistance material there is used a material having a resistivity which increases by at least 100 times with a temperature increase over the range of 20* K. to 373* K.
Claim 2
Dependent Claim
119 words
An arc interrupting device for an electrical circuit comprising at least one main switch and at least one resistor electrically connectable in parallel circuit therewith whose resistance increases with temperature and to which current flowing through said main switch is shifted upon the opening of said switch, characterized by means being present to cool said resistor under normal operating conditions to a temperature between 4* K. and 80* K. and higher than the critical temperature of the material from which said resistor is constructed, and that as said circuit resistance material there is used a material having a resistivity which increases by at least 100 times with a temperature increase over the range of 20* K. to 373* K.
Claim 3
Dependent Claim
66 words
The arc interrupting device of claim 1 having at least one auxiliary switch in parallel connection to said main switch and in series connection with said resistor, characterized by means for opening said auxiliary switch under normal operating conditions when said main switch is closed and for closing said auxiliary switch upon directed opening of said main switch, and just prior to said main switch opening.
Claim 4
Dependent Claim
27 words
The arc interrupting device of claim 2 further characterized by means for closing said auxiliary switch substantially only when said resistor has cooled to a predetermined temperature.
Claim 5
Dependent Claim
84 words
The arc interrupting device of claim 2 particularly for use where rapid reconnection is directed, characterized by the fact that at least two circuits are connected in parallel with said main switch, with each such circuit including one of said resistors and one of said auxiliary switches serially connected across said main switch and wherein means are included to close only that auxiliary switch whose corresponding resistor has cooled to a predetermined teMperature at the time direction is generated for opening said main switch.
Claim 6
Dependent Claim
33 words
The arc interrupting device of claim 1 particularly for use where high magnetic fields are present, characterized by magnetic screening means being present to shield said resistor from the effects of said fields.
Claim 7
Dependent Claim
20 words
The arc interrupting device of claim 1 wherein said resistor is constructed of thin wires or strips connected in parallel.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |