Field experience with high-frequency ballasts

The energy conservation office of the University of California at Berkeley has installed over 35000 high-frequency ballasts, produced by three manufacturers, in the period from 1986 to the present. The quantities of defective ballasts, which are returned to manufacturers for replacement, are used to estimate the failure rate of these ballasts under field conditions. The statistics are believed to provide a good indication of ballast mortality under diverse interior field conditions in terms of absolute ranges of failures as well as in terms of relative performance among models and manufacturers.<>