ingineria iluminatului - Journal of Lighting Engineering - Prof. Florin ...

4.6 LED 37 W Thorn luminaire
A different LED luminaire from the same
manufacturer (Thorn BaseLed Cruz 160
LED 37 W L830 HFX) has been tested. The
dimming process was achieved with the use
of a DALI interface. The measurement
results are presented in Table 6. Figure 8
shows the amplitude variation of the current
harmonics of the light source during the
dimming process (a), and the voltage and
Office lighting with old and new light sources
current wave-shapes (b). As the input signal
level drops, the current amplitude, the
active power, the reactive power, the
apparent power and the power factor have
lower values. At the same time, the THDI
value is increasing. Through the dimming
process, the amplitudes of odd current
harmonics are low, and have relative
constant values. The CRI and CCT do not
suffer any variations.
Table 6 Electric and luminous parameters
Parameter Unit Not dimmed
Dimming levels, set with the DALI system, %
100 80 60 40 20 0
Active power W 39 38.9 26.5 18.2 12.8 8.5 0.5
Reactive power VAR 8.7 8.3 8.4 8 7.5 7.1 4.9
Apparent power VA 39.8 39.8 27.7 19.9 14.8 11.1 5.1
Voltage amplitude V 230 230 230 230 230 230 230
Current amplitude A 0.174 0.173 0.12 0.087 0.064 0.048 0.022
Frequency Hz 50 50 50 50 50 50 50
Power factor 0.98 0.98 0.95 0.91 0.86 0.77 0.95
THDI % 8.34 8.22 13.79 19.35 22.95 25.88 31.87
Luminous flux lm 1960 1960 1430 1015 675 400 0
CRI 79.7 79.7 79.7 79.7 79.7 79.7 -
CCT K 3050 3050 3050 3050 3050 3050 -
Luminous efficacy lm/W 50.26 50.39 53.96 55.77 52.73 47.06 -
(a) (b)
Figure 8 The amplitude variation of the current harmonics of the light source during the dimming process (a),
and the voltage and current wave-shapes (b) at different dimming levels: voltage wave-shape - yellow;
current wave-shape for the not dimmed case - dark blue, and for the mentioned dimming levels (100% - purple;
80% - aqua blue; 60% - brown; 40% - orange; 20% - green; 0% - blue).
Ingineria Iluminatului 2010; 12, 2: 5-22 15