JPS5454467A - Metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To make it easy to start with the power source of 200V by providing a bimetal switch to cut off the discharge circuit between main and auxiliary electrodes in 3 to 120 seconds after lighting, with the current between main and auxiliary electrodes of 0.2A or more and stabilizer short-circuit current of 1/5 or less. CONSTITUTION:Metal halogenide together with mercury and rare gas is enclosed in a luminous tube which has main electrode 2 and 3 and auxiliary electrode 4 which is located adjacent to the main electrode 3. Between main electrode 2 and suxiliary electrode 4, there are resistance 6 for controlling the current between main and auxiliary electrode and bimetal switch 5 connected in series. If the current between main and auxiliary electrodes is kept at 0.2 A or more, arc discharge becomes stable, the main electrode is heated sufficiently and the discharge between the main electrodes becomes easy,, and if starting resistance is selected so that it becomes 1/5 or less of the short-circuit of the stabilizer, voltage drop between the main electrodes becomes 1/4 or less of no-load voltage and start can be made without switching of the bimetal switch.