US4288833A
Expired / Lapsed
US
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Lightning arrestor
Assignee: General Electric Co
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Filing: 1979-12-17
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Granted: 1981-09-08
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Expires: 1999-12-17
Abstract
Abstract A metal oxide varistor (MOV) is directly electrically connected between a line conductor and ground to dissipate the energy associated with voltage surges appearing on the line conductor. A thermostatic switch, in the form of a resilient arm held in electrical connection with one of the MOV electrodes by low melting point solder, opens in response to a failing MOV to insert a spark gap electrically in series with the MOV. Overvoltage protection is thus maintained, albeit limited to higher level voltage surges.
Inventors
- 👤 Edward K. Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:00
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/06; H02H5/00; H02H5/04; H02H5/047; H02H9/042; H01; H01H; H01H37/00; H01H37/74; H01H37/76; H01H37/761; H01H2037/762; H01H2037/763
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
164 words
A lightning arrestor comprising, in combination: A. a voltage-dependent resistor having terminals for electrical connection between a line conductor of a power distribution circuit and ground; B. normally closed thermostatic switch means electrically connected in series with said resistor, said switch means being thermally coupled with said resistor such that heat generated by said resistor in response to excessive leakage current flowing therethrough under normal line voltage conditions causes said switch means to open and thereby interrupt the flow of said excessive leakage current; and C. a spark gap electrically connected in series with said resistor by the opening of said switch means, said spark gap preventing the flow of said excessive leakage current through said resistor and having a predetermined breakdown voltage such as to provide effective distribution circuit overvoltage protection, said resistor acting to dissipate the energy associated with line voltage surges in excess of said breakdown voltage and to insure deionization of said spark gap as each line voltage surge subsides.
Claim 2
Dependent Claim
164 words
A lightning arrestor comprising, in combination: A. a voltage-dependent resistor having terminals for electrical connection between a line conductor of a power distribution circuit and ground; B. normally closed thermostatic switch means electrically connected in series with said resistor, said switch means being thermally coupled with said resistor such that heat generated by said resistor in response to excessive leakage current flowing therethrough under normal line voltage conditions causes said switch means to open and thereby interrupt the flow of said excessive leakage current; and C. a spark gap electrically connected in series with said resistor by the opening of said switch means, said spark gap preventing the flow of said excessive leakage current through said resistor and having a predetermined breakdown voltage such as to provide effective distribution circuit overvoltage protection, said resistor acting to dissipate the energy associated with line voltage surges in excess of said breakdown voltage and to insure deionization of said spark gap as each line voltage surge subsides.
Claim 3
Dependent Claim
16 words
The lightning arrestor defined in claim 1, wherein said voltage-dependent resistor is a metal oxide varistor.
Claim 4
Dependent Claim
23 words
The lightning arrestor defined in claims 1 or 2, wherein the width of said spark gap is on the order of 12 mils.
Claim 5
Dependent Claim
63 words
The lightning arrestor defined in claim 1, wherein said thermostatic switch includes a conductive spring arm deflected from an open circuit position to a closed circuit position sustained by low melting point solder thermally coupled with said voltage-dependent resistor, said arm being released to spring to its open circuit position when said solder is sufficiently melted by the heat developed in said resistor.
Claim 6
Dependent Claim
27 words
The lightning arrestor defined in claim 4, wherein said conductor spring arm is held in direct electrical connection with an electrode of said resistor by said solder.
Claim 7
Dependent Claim
29 words
The lightning arrestor defined in claim 5, wherein said spark gap is constituted by the switch gap established between said electrode and said arm in its open circuit position.
Claim 8
Dependent Claim
19 words
The lightning arrestor defined in claims 4, 5 or 6, wherein said voltage-dependent resistor is a metal oxide resistor.
Claim 9
Dependent Claim
20 words
The lightning arrestor defined in claim 1, wherein said thermostatic switch is electrically connected in shunt with said spark gap.
Claim 10
Dependent Claim
62 words
Lightning arrestor defined in claim 8, wherein said thermostatic switch includes a conductive spring arm deflected from an open circuit position to a closed circuit position sustained by low melting point solder thermally coupled with said voltage-dependent resistor, said arm being released to spring to its open circuit position when said solder is sufficiently melted by the heat developed in said resistor.
Claim 11
Dependent Claim
27 words
The lightning arrestor defined in claim 9, wherein said conductive spring arm is held in direct electrical connection with an electrode of said resistor by said solder.
Claim 12
Dependent Claim
32 words
The lightning arrestor defined in claim 10, wherein said spark gap is constituted by a conductive element directly electrically connected with said arm and supported in closely spaced relation to said electrode.
Claim 13
Dependent Claim
43 words
The lightning arrestor defined in claim 11, and further including a plurality of said conductive elements commonly, directly electrically connected with said arm and commonly supported in closely spaced relation to said electrode such as to provide a plurality of said spark gaps.
Claim 14
Dependent Claim
21 words
The lightning arrestor defined in claims 8, 9, 10, 11 or 12, wherein said voltage-dependent resistor is a metal oxide varistor.
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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) | 1984-09-07 | 1985-03-09 | 1985-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-07 | 1989-03-09 | 1989-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-07 | 1993-03-09 | 1993-09-08 | $7700.00 | Window Closed / Lapsed |