A “Class-A2” ultra-low-loss magnetic ballast for T5 fluorescent lamps

This paper shows that magnetic ballasts for high-voltage T5 lamps are not only feasible but their luminous and ballast-loss performance can be better than those of electronic ballasts. A computer-aided design and practical implementation of an ultra-low-loss magnetic ballast system for T5 28W lamps is presented. The high-voltage & low-current features of T5 lamps imply that the copper and core losses of the magnetic ballast can be greatly reduced. Its total system power is 30W (with a ballast loss of only 2.42W) is less than the 32W upper limit specified for Class A2 of energy-efficient electronic ballast for T5 28W lamps. High luminous efficacy of 74.8 lumen/W can be achieved. This important breakthrough has the potential of reversing the existing trend of using electronic ballasts as the energy-saving technology in lighting industry. With a better luminous efficacy, lower product and maintenance costs, much longer lifetime and the use of recyclable metallic materials over its electronic counterparts, this patent-pending proposal provides a truly sustainable lighting solution to the lighting industry.