Cataphoresis Phenomenon of Fluorescent Lamps with HF Electronic Ballasts.

Abstract

Recently, the T8-4ft. fluorescent lamp systems with high frequency (HF) electronic ballasts have been promoted as a strategic energy-saving product even into the outdoor lighting fields. In such a situation, the troublesome pinkish-colored cataphoresis phenomenon of these lamps is observed especially in the outdoor fields of winter seasons. The cataphoresis phenomenon of FLs is currently considered to occur only in the DC operation and hardly in the AC operation. Nevertheless, conventional HF electronic ballasts keep inherently the superimposed DC voltage component VDC, attributed mostly to the duty unbalance in the HF inverter circuit. This paper shows that the cataphoresis phenomenon of T8-4ft. fluorescent lamp systems with HF electronic ballasts is analyzed in relation to definitive parameters of the coldest tube wall temperature Tc and the superimposed DC voltage component VDC. This has clarified the critical cataphoresis phenomenon outbreak conditions, given by the equation VDC=0.56 Tc-4.3. In addition, through the experiments on the lamp burming hours to the cataphoresis phenomenon outbreak, the ballast design requirement of VDC less than 2V is proposed as an actual suppression measure against the cataphoresis phenomenon.