US 4,350,930 A · Lighting unit

Abstract

A lighting unit is described utilizing an energy efficient metal vapor arc lamp as the main source of light supplemented by a standby filamentary light source producing light when the arc lamp is being started, the filament thereof serving as a resistive ballast for the arc lamp under normal operation. The lighting unit is designed as a more efficient replacement for the incandescent lamp. The lighting unit includes a rectifier for conversion of 60 hertz ac to dc, and a dc energized operating network, including a ferrite transformer and a transistor switch. The operating network produces an output adapted to each operating state of the arc lamp, including the provision of a high ignition potential, a power boost for the lamp during the glow to arc transition, warm-up and ballasting provisions, and means for sustaining the arc during transients which reduce the line voltage. The filamentary light source provides useful standby illumination while the arc lamp is being started, the amount being reduced to a low value as the arc lamp approaches normal light output.

Claims44

Dependent claims

A lighting unit comprising:

A. a dc power source having two output terminals, one a reference terminal,
B. a metal vapor arc discharge lamp requiring energization dependent on its electrical state, and
C. an operating network comprising:
(1) an incandescible resistive filament exhibiting a substantial resistance increase with applied voltage to provide standby light for said lamp,
(2) alternating electrical energy transforming means for coupling a stepped up output voltage to said lamp,
(3) switching means,
(4) interconnecting means for coupling current from said dc source
(a) in a dc form to said filament and said lamp in series for energizing and ballasting said lamp, the dissipation in said filament being too low to produce useful light during normal running operation of said lamp, when said switching means is in a stable first condition, and
(b) in a periodic form to said resistive filament and switching means in series for producing useful light and in a periodic form to the input of said transforming means for starting said lamp, when said switching means is in an astable, second condition, and
(5) means responsive to the electrical conditions of said lamp for maintaining said switching means in said first condition during warm-up and normal running operation of said lamp, and in said second condition during other operating states of said lamp.

7 more elements

A lighting unit adapted to be operated from an electric power source, said unit comprising in combination

A. a metal vapor arc lamp requiring energizing dependent on its electrical state, and
B. an operating network comprising:
(1) an incandescible resistive filament,
(2) alternating electrical energy transforming means for coupling a stepped-up output voltage to said lamp,
(3) switching means, and
(4a) means interconnecting said filament, said switching means, said transforming means and said power source to coupling a periodic current from said power source to said filament for useful light production;
and for coupling a periodic current to the input of said transforming means for starting said lamp, when said switching means is in an astable, second condition, and
(4b) means interconnecting said filament means and said main lamp in series across said power source for energizing and ballasting said lamp at a normal running lamp current at which the dissipation in said filament is low for efficiency, not productive of useful light, when said switching means is in a stable, first condition.

5 more elements

A lighting unit adapted to be energized from an electric power source, said unit comprising in combination:

A. a metal vapor arc lamp requiring energization dependent on its electrical state, and
B. an operating network comprising:
(1) an incandescible filament for providing standby light, having a predetermined resistance and a positive temperature coefficient of resistance,
(2) alternating electrical energy transforming means for coupling stepped-up output voltage to said lamp,
(3) switching means having a stable first condition and an astable second condition,
(4) interconnection means for coupling current from said power source,
(a) in a periodic form to said filament to provide a first useful light output and in a periodic form in the input of said transforming means for starting said lamp, when said switch is in said second condition, and
(b) to said filament means and said lamp in series for energizing and ballasting said lamp when said switching means is in said first condition, the characteristics of said power source, said filament and said lamp being selected to provide a second useful filament light output at the beginning of warm-up of said lamp, and a progressive reduction in filament dissipation, and consequent reduction in filament light output as the light output of said arc lamp progressively rises during warm-up, and
(5) means responsive to the electrical condition of said lamp for maintaining said switching means in said first condition during warm-up and normal operation of said lamp, and in said second condition during other operating states of said lamp.

6 more elements

Dependencies are inferred from the claim text.

Lighting unit

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Lighting unit

Life of this patent

Abstract

Claims44