Impact of Current Crest Factor at High and Low Frequency Operation on Fluorescent Lamp Electrodes

The current crest factor (CCF) is a measure of wave shape distortion and indicates the potential for high peak current, which can damage the lamp electrode and reduce lamp life. The value of 1.7, which is regarded as an acceptable limit by the American National Standards Institute (ANSI) and International Electricity Commission (IEC) ballast performance standards is based on 50/60 Hz operation. High frequency operation involves different electrode operating conditions and the validity of this limit could be questionable. This paper evaluates the relative effect of waveform distortions at high-frequency and the low frequency amplitude modulation of high frequency sinusoidal waveforms on electrode emitter depletion with respect to 60 Hz sinusoidal current steady state operation. The emission of electrode mix is evaluated by barium line measurements and cathode fall monitoring on special-made lamps with clear ends