Effect of power factor improvement on switching life of self ballasted fluorescent lamps

Abstract

This work aims to reveal the underlying effect of improved power factor on the life of Self Ballasted Fluorescent Lamps commonly termed as CFL. In the third world country like India because of cost effectiveness CFLs are still used without any power factor correction circuitry. Recently the power factor improvement tool is made compulsive for CFL and the recommended range as suggested by IEC 61000-3-2 is greater than 0.85. In addition to this the current harmonic distortion is preferred to be around 30% as per the standards. But unfortunately there are still CFLs available in the market which have less power factor in comparison with the desired standards. This has caused substantial problems not only on the generation side, but it certainly has considerable impact on the lamp performance. In the present work in order to exemplify this problem, four CFLs of 15W each from two different manufacturers are used for the experiment. Out of these four lamps, two lamps are ballast with low input power factor and instant start type. The other two are incorporated with improved input power factor having rapid start or warm start circuitry. The lamps are constantly switched ON and OFF at regular intervals. The interval was taken as 5 minutes ON and 5 minutes OFF. The lamps were subjected to this accelerated switching test. At the end of every switching cycle the electrode temperature was calculated from the ratio of hot resistance to cold resistance. It was thus observed that lamps with instant start ballast and poor power factor were unable to sustain the switching stress as compared to the lamps with rapid start ballast and improved power factor. Furthermore, the rise in electrode temperature for the lamps with improved power factor was within the desired standards. Thus it was concluded that lamps with poor power factor was more prone to early end in comparison with the other variety.