Determination of the cathode fall voltage in fluorescent lamps by measurement of the operating voltage

Abstract

A new method for the determination of the cathode fall voltage of fluorescent lamps is shown. The cathode fall voltage can be determined by measurement of the lamp operating voltage at constant lamp wall temperature, constant discharge current and variation of the electrode heating current. Commercial lamps, which do not need to be specially prepared, can be used for the measurement. The results show good correlation to other measurements of the cathode fall voltage at various discharge currents by means of capacitive coupling. The measured values of the cathode fall voltage are used for determining the minimum, target and maximum setting of the sum of the squares of the pin currents of one electrode (the so-called SOS value) as a function of the discharge current in fluorescent lamp dimming.

Secondary electron emission and glow discharge properties of 12CaO·7Al2O3electride for fluorescent lamp applications

“…In a practical fluorescent lamp, visible light is generated by the phosphor, which is excited by the UV light emitted from mercury in the noble-gas discharge plasma [3]. The electron emission properties of the cathode material are closely related to the energy consumption, driving voltage and luminous efficiency of the lamp [4], since the behavior of the discharge plasma is mainly controlled via the surface of the cathode. Metals such as Ni, Mo or W have been generally used as cathode materials for fluorescent lamps.…”

Reducing Barriers To The Use of High-Efficiency Lighting Systems

“…Unfortunately, results from such measurements will only be available after two to three years of testing with much effort and at great expense. Hilscher (2002), from OSRAM GmbH, found a way of acquiring cathode-fall voltage of a fluorescent lamp operated at different discharge and electrode heating current values by measuring the lamp operating voltage. The lamps used in the experiment were 32 W, triple tube compact fluorescent (OSRAM DULUX T/E 32W), operated on 25 kHz electronic ballasts.…”

“…These so called SOS values, given in terms of lamp current, are used as design guides for proper supplemental electrode heating. For the triple tube, 32W compact fluorescent lamp, Hilscher (2002) (Hilscher, 2002) Tetri (2000) conducted a life test on dimming T8 fluorescent lamps operated on dimming ballasts that provided cathode heating. Tetri found that when the lamps were operated at static dim levels of 1%, 5% or 15% luminous flux, or dimmed dynamically up and down according to daylight illuminance levels, the lamp would reach the nominal lamp life and lumen maintenance factor.…”

“…Literature survey T-10 1000 lx initial 500 lx initial Kryszczuk & Boyce, 2001& 2002 • Lower frequency • Investigated how fast illuminance could be reduced before change is noticed.…”

“…T-11 Kryszczuk & Boyce, 2001& 2002 • Detection threshold for slow light level reduction is independent of the rate of change.…”