Discussion, with reply, of "Field experience with high-frequency ballasts

The commenter formulates two questions for the author of the above-named paper (see ibid., vol.26, no.5, pp.810-11, 1990). The commenter points out that high-frequency ballasts typically use full-wave rectifiers to supply DC-AC inverters. He asks whether the author has found the power factor to be quite low and a significant harmonic content of the line current. He also asks whether these ballasts can be used with a DC power source. The author replies that; (1) high-frequency ballasts are commercially available with power factors in the range of 85-90%-the latest versions have less than 20% of third-harmonic content, and he has experienced no problems attributable to harmonic content during the course of installing over 70000 high-frequency ballasts at the University of California at Berkeley; and (2) DC sources can be used with high-frequency ballasts-however, it will probably prove necessary to modify either the existing DC source or the commercially available ballast in order to ensure compatibility.<>