Abstract: This reactor ballast is used for controlling a lamp and comprises a core and winding connected in circuit with the lamp and inductively coupled to the core for developing a magnetic field in the core when the winding is traversed by electric current. The core forms a magnetic circuit for the magnetic field comprising two parts in series with each other in the magnetic circuit, one part being of metallic magnetic material and the other being of ferrite material. A control arrangement is provided for varying the temperature of at least a portion of the ferrite part in a predetermined temperature range just below the Curie point of the ferrite material where its relative permeability decreases steeply in response to small temperature increases.

Abstract: A spark gap device is disclosed that is particularly suited for a rapid restrike or starting circuit which is employed in sport stadium lighting applications to start or restrike metal halide lamps that have been subjected to a momentary loss of power. The spark gap device comprises two electrodes that are arranged in a parallel side-by-side relationship and spaced apart from each other by a predetermined amount. The spark gap device operates that when a high voltage potential is applied across the electrodes, the generated and reoccuring spark is distributed along the parallel arranged electrodes. The parallel arrangement of electrodes provides for improved life and cooler electrode temperatures as compared to prior art spark gap devices in which the generated and reoccuring spark jumps between the end regions of separated electrodes.

Abstract: Containment means for a luminaire that captures hot particles created by the unlikely event of a pressurized lamp rupture is disclosed. In one embodiment, the containment means comprises a mesh interposed between the lamp and a refractor of the luminaire typically formed of an acrylic material. The mesh captures hot particles having a sufficient heat capacity and temperature to create excess heat damage to the refractor.

Abstract: A compacted powdered iron core utilizes iron powder in the 0.002 to 0.006 mean particle size range which is firt coated with an alkali metal silicate and then overcoated with a silicone resin polymer. The treated powder is compressed to approximately 94% of theoretical density and then annealed at approximately 600.degree. C. This results in a core component characterized by overall core losses as low as in conventional laminated cores in A.C. operation.

Abstract: A compacted powdered iron core utilizes iron powder in the 0.002 to 0.006 mean particle size range which is first coated with an alkali metal silicate and then overcoated with a silicone resin polymer. The treated powder is compressed to approximately 94% of theoretical density and then annealed at approximately 600.degree. C. This results in a core component characterized by overall core losses as low as in conventional laminated cores in A.C. operation.

Abstract: Luminaire provides relatively uniform illumination in substantially rectangular pattern up and down the roadway adjacent the luminaire. The luminaire reflector is formed with a multiplicity of flat facets individually oriented to direct light to particular areas along the roadway surface.

Abstract: Circuit operating from a direct current source applies DC pulses to a high pressure sodium vapor lamp to improve the color properties of the lamp. In one embodiment, the circuit includes a charging circuit comprising a first inductor, a diode and a capacitor connected across the DC source, and a discharging circuit comprising a second inductor of lower inductance than the first inductor, a controlled thyristor switch and sodium vapor lamp connected across the capacitor, and a timing circuit for periodically turning on the switch at predetermined intervals. A third inductor and a serially connected diode are connected across the discharging circuit to prevent excessive voltage across the controlled switch and to provide for control of lamp wattage with respect to changes in lamp voltage.

Abstract: Circuit operating from a direct current source applies DC pulses to a high pressure sodium vapor lamp to improve the color rendition of the lamp. The circuit includes a thyristor switch in series with the lamp, an RC timing circuit for periodically turning on the switch at predetermined intervals, and an LC circuit for turning the switch off. An inductor in series with a diode across the capacitor of the LC circuit provides for discharge of the capacitor to enable subsequent re-charging thereof, so as to provide the desired pulsed operation of the circuit. This mode of operation also provides for application of voltage to the lamp which is substantially higher than the supply voltage.

Abstract: Spectral output of lamp is controlled by a combination of color filters and dual photocell which monitors the spectral composition of the radiant energy from the lamp and compensates for change therein by automatically varying the power applied to the lamp to provide constant spectral output.