GB1161948A - Starting Device for Gas-Discharge Lamps - Google Patents

Abstract

1,161,948. Supply systems for discharge lamps. SENTA - DORIS GRIEDER - ZIMMERLI. 15 Feb., 1967 [15 Feb., 1966], No. 7291/67. Heading H2H. A xenon long arc lamp 7 is started and supplied by the circuit shown in the Figure in which a transformer 1 is connected to an A.C. supply 3 and has an output voltage at least equal to the rated operating voltage of the lamp but substantially lower than the lamp ignition voltage, and an additional transformer 15 has a primary winding 19 connected to an A.C. supply 11 and a secondary winding 17 which boosts the circuit voltage to the ignition value. To start the lamp, a manually-operated switch 13 is closed to energize a conventional high frequency starting device 5 from the supply 11, the winding 19 being energized through a switch 21 whose control coil 23 is supplied from a current transformer 25 in the lamp circuit. When the current therein reaches a predetermined value corresponding to lamp operation, the switch 21 is opened to de-energize the winding 19 and allow the winding 17 to act as a ballast for the lamp, the core of transformer 15 being saturated by the lamp current. Operation of the relay arrangement 21, 23 may be achieved in alternative ways, e.g. using magnetic, capacitive or photo-electric means, this last method being responsive to the light emitted by the lamp. The transformer 25 may be combined with the transformer 15 which would then have a third winding supplying the coil 23, or may be omitted in which case the coil 23 is connected directly in the lamp circuit. The light output of the lamp may be varied by providing the transformer 15 with a D.C. energized winding to vary the saturation of the core, this winding being energized after ignition of the lamp by further contacts controlled by the coil 23, Fig. 4 (not shown). Each of the windings of transformer 15 may comprise two halves wound on separate cores and connected series-aiding in the case of windings 17, 19, and series-opposing in the case of the D.C. energized winding, Fig. 4 (not shown). In another modification, Fig. 5 (not shown), the transformer 25 supplies another coil (53) whose contacts (55) bridge part or all of the winding 17, the relay arrangement (53, 55) having a time delay so that part or all of the winding 17 is short circuited at a predetermined time after de-energization of the winding 19. Circuits are described, Figs. 2 and 3 (not shown), in which two or three lamps, each supplied as shown in the Figure, are operated from a three phase A.C. supply using separate or combined transformers 1.