Accelerating Start-up of Metal Halide Lamps

Experiments are conducted to investigate the starting characteristics of metal halide lamps ballasted with a controllable low-frequency square-wave current. Several starting scenarios are examined to learn the different acceleration schemes of the start-up transient. Experimental evidence shows that the starting time of a metal halide lamp can be effectively shortened by increasing the lamp current during the glow-to-arc transition stage. More importantly, a specifically-regulated operating power enables the lamp to further enhance the producing of luminance, and hence greatly reduce the starting transient period