Characteristics of electrodeless ferrite-free fluorescent lamp operated atfrequencies of 1-15 MHz

A RF electrodeless ferrite-free fluorescent lamp with a re-entry cavity was studied at driving frequencies, f = 1.2-15.0 MHz and RF power up to 80 W. Induction coils with different numbers of turns, from 6 to 26, were used to ignite and maintain the inductively coupled RF discharge in the lamp bulb. The lamp ignition and operational parameters (such as coil starting and ma intaining voltages and currents, lamp impedance and resistance, starting po wer and coil power losses) were directly measured. The transformer model of an RF inductive discharge was applied to calculate the discharge parameter s: plasma resistance and current, plasma effective RF electric field and pl asma e-factor. The results of the calculations are in good agreement with t he experimental data published elsewhere. Due to low power losses in the in duction coil with large number of turns (26), the power efficiency of the l amp at the frequency of similar or equal to 2.65 MHz was high, 92%, which p rovided high lamp efficacy of 83 lumen per watt (LPW) at a RF power of 60 W .