Abstract: A method and apparatus for reducing ripple current in a projector lamp comprising an electrical network comprising input terminals A and C, and output terminals B and D, including a first inductive element and a second inductive element, each inductive element having a first terminal and a second terminal, with the second terminal of the first inductive element electrically connected with the second terminal of the second inductive element at output terminal B, with the first terminal of the first inductive element connected to input terminal A, and the first terminal of the second inductive element connected to input terminal C; and a means for impressing a first source of switching potential from an external source at input terminal A, and a second source of switching potential from the external source out-of-phase with the first source of switching potential, at input terminal C such that a ripple current across the output terminals B and D is minimum.

Abstract: A safety interlock apparatus for an electrical device includes a DC power supply, a ballast power supply including a ballast control circuit that controls a ballast power circuit, and a lamp. A relatively low voltage electrical connection is present between the DC power supply and the ballast control circuit. A relatively high voltage electrical connection is present between the lamp and the ballast power circuit. A safety interlock switch is positioned on the relatively low voltage electrical connection, the switch having a closed state wherein the relatively low voltage is supplied to the ballast control circuit and an open disconnected state wherein the relatively low voltage electrical connection is disconnected. A panel is fixable to the electrical device frame, and is selectively movable to expose the lamp for removal.

Abstract: An arc lamp igniter circuit (10) employs a resonant inverter circuit (16) to convert low-voltage DC to a relatively high-voltage, 80 kilohertz sinusoidal AC voltage that is rectified and voltage-doubled (42, 44, 46) to about 2,500 volts DC for repetitively charging an igniter capacitor (50) until it discharges through a spark gap (58) and a primary winding (54) of a compact, low-mass igniter transformer (52). A secondary winding (56) of the igniter transformer provides repetitive 20 kilovolt pulses, which are sufficient to ionize a metal halide arc lamp (14), causing it to ignite and produce intense illumination.

Abstract: A removable lamp module (14) employs a male (26) and female (22) electrical connector (24) pair that serves multiple functions including connecting a lamp power supply (72) and high-voltage lamp igniter circuit (74) to an arc lamp (39), acting as a safety interlock switch, and mechanically latching the lamp module within a projector cavity (13). The lamp module safely encloses the arc lamp, provides an airflow pathway for cooling the arc lamp, and slidably secures (50) the male half of the connector pair. The lamp module slides in a first direction into the cavity, and the male half of the connector pair slides in a second direction, transverse to the first direction, into engagement with the female half of the connector pair to latch the lamp module within the projector cavity. Replacing the arc lamp entails sliding the connector pair out of engagement, removing the lamp module from a projector enclosure (12), and replacing the lamp.

Abstract: A circuit arrangement controls power to a fluorescent lamp rather than controlling current. Since light output is proportional to power, flicker control is improved and lamp life is extended.

Abstract: An aircraft wing inspection light system used to illuminate an aircraft's wing to permit ice detection from inside the cabin. The aircraft wing inspection light system utilizes an arc lamp to provide enough light for the power available. In addition to the arc lamp, the aircraft wing inspection light system is further comprised of a housing, a lampholder, a lens, a reflector, a ballast which contains a power supply and a connecting means for connecting the lampholder to the ballast.