US3787751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ballast circuits for discharge lamps
Assignee: EMI Group Ltd
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Filing: 1972-08-10
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Granted: 1974-01-22
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Expires: 1992-08-10
Abstract
Abstract A ballast circuit for a discharge lamp is arranged to supply a uni-directional voltage to the lamp which is made up of at least two current components which differ in phase. Flicker at the supply frequency f and at 2f is thus much reduced. A preferred ballast for use with a three-phase supply employs ballast capacitors in each of the three supply lines connected to a three-phase bridge rectifier, the output of which is applied to the lamp. A preferred ballast for use with a single phase supply includes a ballast capacitor and a ballast inductor connected through respective bridge rectifiers which have some components in common.
Inventors
- 👤 V Farrow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:37
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/16; H05B41/20; H05B41/23; H05B41/232; Y; Y10; Y10S; Y10S315/00; Y10S315/05
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
92 words
A ballast circuit for a discharge lamp, comprising: first and second input terminals for receiving an alternating voltage; first and second output terminals for applying a uni-directional voltage to a discharge lamp; two oppositely-poled diodes connected between said first input terminal and said first and second output terminals respectively; a capacitor and an inductor both connected to said second input terminal; two oppositely-poled diodes connected between said capacitor and said first and second output terminals respectively; and two oppositely-poled diodes connected between said inductor and said first and second output terminals respectively.
Claim 2
Dependent Claim
92 words
A ballast circuit for a discharge lamp, comprising: first and second input terminals for receiving an alternating voltage; first and second output terminals for applying a uni-directional voltage to a discharge lamp; two oppositely-poled diodes connected between said first input terminal and said first and second output terminals respectively; a capacitor and an inductor both connected to said second input terminal; two oppositely-poled diodes connected between said capacitor and said first and second output terminals respectively; and two oppositely-poled diodes connected between said inductor and said first and second output terminals respectively.
Claim 3
Dependent Claim
83 words
In combination with a discharge lamp, a ballast circuit comprising: three input terminals for connection to a three-phase alternating current supply; two output terminals for applying a uni-directional voltage to said discharge lamp; three ballast capacitors each connected to a respective input terminal; and a three-phase bridge rectifier connected between said capacitors and said output terminals, whereby said voltage applied to said discharge lamp has a ripple frequency which is six times the frequency of the alternating current received by said input terminals.
Claim 4
Dependent Claim
83 words
In combination with a discharge lamp, a ballast circuit comprising: three input terminals for connection to a three-phase alternating current supply; two output terminals for applying a uni-directional voltage to said discharge lamp; three ballast capacitors each connected to a respective input terminal; and a three-phase bridge rectifier connected between said capacitors and said output terminals, whereby said voltage applied to said discharge lamp has a ripple frequency which is six times the frequency of the alternating current received by said input terminals.
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) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |