Ferrite-free high power electrodeless fluorescent lamp operated at a frequency of 160-1000 kHz

摘要

An electrodeless ferrite-free fluorescent lamp of a closed-loop type ('tokamak') was studied at a driving frequency, f = 160-1000 kHz, and power of 100-250 W. The inductive discharge was ignited in the mercury-argon mixture with the help of an induction coil of several (7-15) turns made from multiple-strand (Litz) wire. The discharge parameters-current, resistance, and electric field-were calculated using the transformer model of an RF inductive discharge. They were found to be close to those measured in a plasma of a 'tokamak'-type lamp operated at the same frequency and RF power but with the use of the ferrite cores [11]. The ferrite-free lamp had high luminous efficacy as high as 85 LPW at a frequency, f > 200 kHz, and power of 100-200 W. Such a high efficacy is attributed to low coil power losses (< 15 W) and hence to high lamp power efficiency, η > 90%. [References: 11]