GB722315A - Improvements in apparatus for starting and operating gaseous discharge devices - Google Patents

Abstract

722,315. Supply systems for space-discharge apparatus; transformers. ADVANCE TRANSFORMER CO. Dec. 21, 1950 [Dec. 29, 1949], No. 31184/50. Classes 38 (2) and 38 (4). Two gaseous discharge devices, e.g. fluorescent lamps 24, 25, are connected to a starting and operating transformer 10 or 10<SP>1</SP> which comprises an elongated shell-type magnetic iron core 14, 15 which forms a single magnetic circuit, a primary winding 11 connected across an A.C. source 31 of voltage insufficient to ignite either device, and first and second secondary windings 12, 13 magnetically coupled to the primary winding and series connected end to end in the order stated with the first secondary winding 12 connected between the other two windings 11, 13, the second secondary winding 13 being mounted at one end of the core, the primary winding 11 at the centre of the core, and the first secondary winding 12 at the other end of the core and spaced, e.g. with the interposition of shunts 16 and air gaps 17, from the other two windings to give it a very high leakage reactance; the first device is connected across at least the first secondary winding 12 but not the second secondary winding 13, the second device is connected across at least both the secondary windings 12, 13, which latter are connected in voltage opposition at open circuit, and the first secondary winding 12 provides a high initial voltage to start the first device whereafter it provides a component in phase with the second secondary winding 13 to start the second device, and presents a high impedance during running to force the major flow of current through the series circuit of the two devices and the second secondary winding 13. Alternatively to the lamp connections shown, the first lamp may be connected across only the first secondary winding and the second lamp across all three windings, and in both cases a condenser 26 may be serially connected with the first device to correct the P.F. and to assist the voltage phase shift of the first secondary winding. Specification 565,843 is referred to.