US3727104A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective circuit for lighting system
Assignee: General Electric Co
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Filing: 1971-12-08
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Granted: 1973-04-10
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Expires: 1991-12-08
Abstract
Abstract Solid state protective circuit for reducing high open circuit voltage across lamps in secondary circuit of constant current regulator system. The protective circuit includes a triac connected across the lamp load and triggered into conduction by a circuit connected to the triac gate electrode and comprising series-connected capacitor and resistor which triggers the triac upon a rapid rate of rise of the open circuit voltage.
Inventors
- 👤 W Neal
- 👤 N Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:06
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/041; H02H7/00; H02H7/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
176 words
In a constant current regulator system having a load circuit characterized by a high open circuit voltage with a steep wavefront, a load series connected in the load circuit, and a protective circuit for reducing the high open circuit voltage across the load upon failure or removal thereof, said protective circuit comprising a controlled bilateral semiconductor switch connected across said load, said switch having a control electrode adapted when energized to trigger said switch into conduction, said switch having a first terminal adjacent said control electrode and a second terminal remote from said control electrode, and a capacitor connected from said second terminal to said control electrode, said capacitor having a reactance to the relatively steep wavefront of the high open circuit voltage which is considerably lower than its reactance to the relatively gradual wavefront of the normal operating voltage of the load circuit, said capacitor operating upon occurrence of an open circuit at said load to energize said control electrode for triggering said switch into conduction, whereby the voltage across the inoperative load is reduced.
Claim 2
Dependent Claim
176 words
In a constant current regulator system having a load circuit characterized by a high open circuit voltage with a steep wavefront, a load series connected in the load circuit, and a protective circuit for reducing the high open circuit voltage across the load upon failure or removal thereof, said protective circuit comprising a controlled bilateral semiconductor switch connected across said load, said switch having a control electrode adapted when energized to trigger said switch into conduction, said switch having a first terminal adjacent said control electrode and a second terminal remote from said control electrode, and a capacitor connected from said second terminal to said control electrode, said capacitor having a reactance to the relatively steep wavefront of the high open circuit voltage which is considerably lower than its reactance to the relatively gradual wavefront of the normal operating voltage of the load circuit, said capacitor operating upon occurrence of an open circuit at said load to energize said control electrode for triggering said switch into conduction, whereby the voltage across the inoperative load is reduced.
Claim 3
Dependent Claim
25 words
A device as defined in claim 1, including a resistor connected from said first terminal to the junction of said control electrode and said capacitor.
Claim 4
Dependent Claim
38 words
A device as defined in claim 2, said capacitor operating to energize said control electrode when the rate of rise of said open circuit voltage is at least twice the rate of rise of said normal operating voltage.
Claim 5
Dependent Claim
41 words
A device as defined in claim 3, said constant current regulator system having an output circuit including an isolating transformer series connected in said output circuit and having a secondary winding connected to said load circuit in series with said load.
Claim 6
Dependent Claim
35 words
A device as defined in claim 4, wherein said output circuit comprises a plurality of series connected isolating transformers, each having a load connected thereto with a protective circuit as defined connected across the load.
Claim 7
Dependent Claim
12 words
A device as defined in claim 1, said load comprising lamp means.
Claim 8
Dependent Claim
79 words
A device as defined in claim 2, a voltage sensitive bilateral switch having a predetermined breakdown voltage connected in series with said control electrode, and an auxiliary capacitor connected to said voltage sensitive bilateral switch in parallel with said resistor, said auxiliary capacitor being charged by said first mentioned capacitor upon the appearance of the high open circuit voltage and operating upon reaching said breakdown voltage to discharge through said voltage sensitive bilateral switch for energizing said control electrode.
Claim 9
Dependent Claim
16 words
A device as defined in claim 7, said voltage sensitive bilateral switch comprising a semiconductor switch.
Claim 10
Dependent Claim
15 words
A device as defined in claim 8, said semiconductor switch comprising a silicon bilateral switch.
Claim 11
Dependent Claim
150 words
A protective circuit arrangement comprising, in combination, controlled bilateral switch means adapted to be connected across a load subject upon failure to a high open circuit voltage characterized by a steep wavefront, said switch means having a control electrode adapted when energized to trigger said switch means into conduction, said switch means having a first terminal adjacent said control electrode and a second terminal remote from said control electrode and a capacitor connected from said second terminal to said control electrode, said capacitor having a reactance to the relatively steep wavefront of the high open circuit voltage which is considerably lower than its reactance to the relatively gradual wavefront of the normal operating voltage of the load, said capacitor operating upon occurrence of an open circuit at the load to energize said control electrode for triggering said switch means into conduction, whereby the voltage across the inoperative load is reduced.
Claim 12
Dependent Claim
150 words
A protective circuit arrangement comprising, in combination, controlled bilateral switch means adapted to be connected across a load subject upon failure to a high open circuit voltage characterized by a steep wavefront, said switch means having a control electrode adapted when energized to trigger said switch means into conduction, said switch means having a first terminal adjacent said control electrode and a second terminal remote from said control electrode and a capacitor connected from said second terminal to said control electrode, said capacitor having a reactance to the relatively steep wavefront of the high open circuit voltage which is considerably lower than its reactance to the relatively gradual wavefront of the normal operating voltage of the load, said capacitor operating upon occurrence of an open circuit at the load to energize said control electrode for triggering said switch means into conduction, whereby the voltage across the inoperative load is reduced.
Claim 13
Dependent Claim
25 words
A device as defined in Claim 10, including a resistor connected from said first terminal to the junction of said control electrode and said capacitor.
Claim 14
Dependent Claim
39 words
A device as defined in claim 11, said capacitor operating to energize said control electrode when the rate of rise of the open circuit voltage is at least twice the rate of rise of the normal load operating voltage.
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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) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |