The Interaction of Metal Halide Lamps and Ballasts during Reignition

Abstract

We have studied the reignition of metal halide lamp arcs after current zero, particularly during the warm-up period when reignition difficulties sometimes cause the lamps to extinguish. We used both mathematical and analog models to understand the lamp-ballast interface so as to separate the respective roles of the lamp and ballast during reignition. Our measurements of the arc conductance during the reignition period allow us to make some conclusions about physical processes at the cathode. We also measured and evaluated the reignition requirements of several types of metal halide lamps and the reignition capability of various commercial ballasts.