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

Abstract

A RF electrodeless ferrite-free fluorescent lamp with a re-entrycavity was studied at driving frequencies, f = 1.2-15.0 MHz and RFpower up to 80 W. Induction coils with different numbers of turns, from 6 to26, were used to ignite and maintain the inductively coupled RF dischargein the lamp bulb. The lamp ignition and operational parameters (such ascoil starting and maintaining voltages and currents, lamp impedance andresistance, starting power and coil power losses) were directly measured.The transformer model of an RF inductive discharge was applied to calculatethe discharge parameters: plasma resistance and current, plasma effectiveRF electric field and plasma Q-factor. The results of the calculations arein good agreement with the experimental data published elsewhere. Due tolow power losses in the induction coil with large number of turns (26), thepower efficiency of the lamp at the frequency of ≃2.65 MHz washigh, 92%, which provided high lamp efficacy of 83 lumen perwatt (LPW) at a RF power of 60 W.