GB592042A - Improvements relating to fluorescent lighting systems - Google Patents

Abstract

592,042. Supply systems for space discharge apparatus. MANDL, A., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Aug. 31, 1944, No. 16568. [class 38 (iv)] In a fluorescent lighting system comprising a a plurality of lamps connected for supply from a variable voltage alternator, a master switch is operable to produce an inductive voltage across the lamps for starting. In the arrangement of Fig. 1, for lamps with " cold " electrodes, the alternator A.C. is short-circuited by switch S, which is opened, after the alternator has been excited, to produce an inductive starting voltage across lamp circuit C<1>, L1; C2, L2; C3, L3, &c. The alternator excitation from a constant voltage A.C. supply B is controlled by a regulator R, the actuating coil of which is energized by D.C. derived from a " dummy " lamp circuit CD, RD, such as to maintain constant voltage across the lamps during normal operation. Condenser C may be included to compensate for alternator internal inductance. Lamps L1 ... L4 of the preheated filament type (Fig. 2), have their filaments connected in series with transformers T1 ... T4, the secondaries of which are connected in series, parallel, or series-parallel through a master switch S, which is closed to heat the lamp filaments. When switch S is opened an inductive starting voltage occurs across each lamp. The circuit for the actuating coil of regulator R which is energized from the current transformer T includes an auxiliary switch AS opened with the switch S to increase current in the coil and reduce the alternator voltage for normal running.