Characterization of Non-Stable States of Lamp Operation of High Power Lamps

High power medium pressure mercury containing lamps used as UV sources for curing of varnish and for water purification are investigated. The intention of the work is to characterize non-stable states of lamp operation with respect to an electronic operation. For that purpose a combination of emission spectroscopy and thermography is used to determine spectra, plasma parameters and the lamp temperature. The lamps work stable at the nominal power of 35 kW but there are changes in the lamp behavior for decreasing the input power. The influence of acoustic resonances is investigated. Recommendations for an optimization of the lamp system to avoid a disadvantageous lamp operation are worked out.