Patent US3631322A successfully refreshed from Google Patents.
US3631322A
Expired / Lapsed
US
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Fluorescent lamp ballast protector means and method
Assignee: Texas Instruments Inc
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Filing: 1969-12-04
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Granted: 1971-12-28
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Expires: 1989-12-04
Abstract
Abstract A fluorescent lamp ballast protector which senses and limits the amount of heat generated within a ballast, thereby keeping temperature in the ballast within a preselected temperature limit to avoid deleterious effects on insulation comprises a heatresponsive layer of material having negligible resistance at temperatures below a threshold and a resistance which increases by several orders of magnitude per degree at temperatures above the threshold. The layer is preferably placed in optimum heattransfer relation with the windings and electrically connected in series relation between a power source and the ballast. The sensor/protector can be mounted on a separate heat-conductive member to enhance heat transfer.
Inventors
- 👤 Curtis F Kruger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:57
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/46; H02; H02H; H02H5/00; H02H5/04; H02H5/042
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
The method of protecting fluorescent lamp ballasts from deleterious excessive temperatures due to a fault condition in a component of the ballast comprising: taking a layer of material having a resistance of approximately 1 ohm and having a threshold temperature above which the resistance rises several orders of magnitude, placing the layer in heat-transfer relation to the windings of the ballast, electrically connecting the layer between a power source and the ballast, whereby the temperature within the ballast will be limited to a desired maximum value by a decrease in current in the windings.
Claim 2
Independent Claim
94 words
The method of protecting fluorescent lamp ballasts from deleterious excessive temperatures due to a fault condition in a component of the ballast comprising: taking a layer of material having a resistance of approximately 1 ohm and having a threshold temperature above which the resistance rises several orders of magnitude, placing the layer in heat-transfer relation to the windings of the ballast, electrically connecting the layer between a power source and the ballast, whereby the temperature within the ballast will be limited to a desired maximum value by a decrease in current in the windings.
Claim 3
Dependent Claim
16 words
The method of claim 1 where the layer has a threshold temperature of approximately 105* Centigrade.
Claim 4
Dependent Claim
13 words
The method of claim 1 where the layer is lanthanum doped barium titanate.
Claim 5
Dependent Claim
12 words
The method of claim 1 where the layer is carbon black-filled polyethylene.
Claim 6
Dependent Claim
80 words
In a fluorescent lamp ballast comprising transformer primary and secondary windings and a condenser, the combination witH said ballast of a sensor/protector comprising a layer of PTC material having a relatively constant resistance of negligible quantity at temperatures below a selected threshold and a resistance which increases by several orders of magnitude with temperature above the threshold, the layer supported in heat-transfer relation with the ballast windings and electrically connected in series relation between a power source and the ballast.
Claim 7
Dependent Claim
80 words
In a fluorescent lamp ballast comprising transformer primary and secondary windings and a condenser, the combination witH said ballast of a sensor/protector comprising a layer of PTC material having a relatively constant resistance of negligible quantity at temperatures below a selected threshold and a resistance which increases by several orders of magnitude with temperature above the threshold, the layer supported in heat-transfer relation with the ballast windings and electrically connected in series relation between a power source and the ballast.
Claim 8
Dependent Claim
19 words
The structure according to claim 5 in which conductive layers are attached to spaced portions of the PTC layer.
Claim 9
Dependent Claim
23 words
The structure according to claim 5 in which the sensor/protector is attached to a thermally conductive plate and the plate bridges the windings.
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) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |