1 Abstract - Lighting Laboratory
Helsinki University of Technology, Lighting Laboratory E s p o o 2 0 0 1
LAMP LIFE
Eino Tetri
H e l s i n k i U n i v e r s i t y o f T e c h n o l o g y D e p a r t m e n t o f E l e c t r i c a l a n d C o m m u n i c a t i o n s E n g i n e e r i n g L i g h t i n g L a b o r a t o r y R e p o r t 2 7
H e l s i n k i U n i v e r s i t y o f T e c h n o l o g y L i g h t i n g L a b o r a t o r y P . O . B o x 3 0 0 0 0 2 0 1 5 H U T T e l . + 3 5 8 9 4 5 1 4 9 7 1 F a x + 3 5 8 9 4 5 1 4 9 8 2 E - m a i l : l i g h t l a b @ h u t . f i I S B N 9 5 1 - 2 2 - 5 4 5 3 - 0 I S S N 1 4 5 5 - 7 5 4 1 O t a m e d i a O y E s p o o 2 0 0 1
Contents
3.1.3 Phase 3 – Dynamic dimming...................................................................12
3.2.3 Phase 3 – Dynamic dimming...................................................................17
1
Abstract
Large lighting energy savings are possible in offices by the use of automatic lighting control system. A control system based on daylight makes great demands on lamps and electronic ballasts. If it is aimed to keep constant horizontal illuminance, the artificial lighting changes according to the quick and large variations of daylighting. The main objectives of the study were to establish proven relationships between lamp drive, cathode heating, dimming levels, dimming dynamics and lamp life. Lamp life was studied with a lamp life test. There were 24 test groups and in each test group there were 15 lamps. Lamps were from 5 different manufacturers, 3 lamps from each. Six test groups were burned undimmed with three hours burning cycle. Twelve groups were burned with luminous fluxes dimmed to 1 %, 5 % or 15 %. Burning cycles were three hours. Six test groups were dimmed dynamically. In addition of commercially available electronic ballasts, there were modified electronic ballasts. In modified ballasts the heating current to cathodes had been adjusted to -10 %, +10 % or +20 % of the current of regular ballasts. When lamps were burned statically on low light levels, the lumen maintenance was higher compared to burning on full light level. When lamps were dimmed dynamically without breaks (Dynamic 3), the lumen maintenance was also higher than when lamps were burned on full light level. However, when lamps were dimmed dynamically and the switching cycle was 2.1 times or 1.6 times higher than the standard 3 hour burning cycle on full light level, the lumen maintenance was little lower in the dynamic test groups. The difference in lumen maintenance was anyhow only one to two percentage unit. The effect of cathode heating level on lumen maintenance is negligible compared to the effect of dimming on lumen maintenance. The dimming of lamps shorten their lives. The effect of dimming on lamp life is bigger if the cathode heating level is not optimal. The cathode heating level has a clear effect on lamp life. After 12 000 burning hours the mortality of the static dimming groups was 62 % with -10 % cathode heating level, 4 % with nominal level, 9 % with +10 % level and 24 % with +20 % level. The mortalities of the dynamic dimming groups were 4 % with nominal cathode heating level and 11 % with +20 % level. Too small cathode heating current is more disastrous to the lamp life than too big heating current. Lamps can be burned continuously on low light levels and be dimmed dynamically without affecting the lumen maintenance so much that it would shorten the economical lamp life. With proper cathode heating level the lamp will reach the nominal lamp life both if the lamp is dimmed statically or dynamically. The lamp or the electronic ballast is not an obstacle for wider use of daylight with artificial lighting. 2
1 Introduction
1 Introduction
Fluorescent lamps can be dimmed according to daylight, using dimmable ballasts and a sensor that measures daylight. By using automatic lighting control, it is possible to reduce the use of lighting energy between 30 % and 70 %. Savings are dependent on the point of compass, the size and shape of the window, and shape and surface reflectances of the room. When old luminaires with conventional ballast are replaced with new ones with electronic ballasts, 20… 25 % of energy has already been saved. (Halonen 1997) To achieve the theoretical savings, the lighting control system should be automatic, perhaps with a possibility for manual control. Fluorescent lamps can be dimmed according to daylight using dimmable ballasts and a sensor that measures the daylight. It is advisable to dim the lamps near the window more than the lamps that are further from the window. Thus the visual conditions are kept good and balanced for all. Daylight is generally experienced as comfort visual environment. The efficiency of lighting control system is determined not only by the energy savings but also how it fulfils the requirements for good visual environment and users´ needs. A control system based on daylight makes great demands on lamps and ballasts. For instance, on a semi-cloudy day the daylight levels inside can vary very rapidly. If an artificial lighting system is adjusted to keep the lighting level constant, it has to dim the lamps continuously and quite quickly as Figure 1 shows. (Halonen & Lehtovaara 1997) 10 Dimming voltages Measured vertical window illuminance 12000 8 6 8000 Ev 4 4000 2 volt1 volt2 a) 0 0 1 2 time from the s 3 4 b) 0 0 1 2 time from the s 3 4 3
2 Methods
2 Methods
2.1 Lamp life test
Lamp life in dimming use was studied with a lamp life test. The main objectives were to establish proven relationships between lamp drive, dimming levels, dimming dynamics and lamp life. Lamps were burned in open test racks. The supply voltage to test racks was fed through voltage stabilisers. The supply voltage was 230 V and the frequency was 50 Hz. The rated voltage and frequency declared by the manufacturer were 230-240 V and 50-60 Hz respectively. The temperature of the test room was +22 ° C ± 5 ° C. Lamps were checked five times a week. The ambient circumstances were: − Burning cycle • Phase 1 and Phase 2 • Phase 3: 3 hour burning cycle, 2 h 45’ on and 15’ off Dynamic 1 two breaks in 2 h 55’ − cathode heating levels • nominal, –10 %, +10 %, +20 % − dimming levels • 100 %, 15 %, 5 %, 1% − dimming dynamics • no dimming Dynamic 2 two breaks in 4 h 10’ Dynamic 3 no breaks • static, three-hour burning cycle • dynamic, three different dynamics
Figure 2. Lamp life test. Lamps were burned in open test racks.
4
2 Methods There were 24 test groups, which were divided in three phases. In each test group there were 15 lamps. Lamps were from 5 different manufacturers 3 lamps from each. Lamp life test conditions are in Table 1.
Table 1. Lamp life test groups.
Phase 1
Ballast Magnetic ballast Helvar EL 1x36 HF Electronic ballast
Phase 2
Dimming levels 1 % 5 % 15 %
Phase 3
Dynamic Undimmed nominal 1 2 3 Cathode heating –10% 4 +10% 5 Effect of dimming on lamp life Ballasts Helvar EL 1x36 AC Cathode heating nominal –10% +10% 7 11 8 12 9 13 15 16 17 Dynamics, effect of daylight use in lamp life Ballasts Helvar EL 1x36 AC Cathode heating nominal 19 21 +20% 20 22 +20% 6 +20% 10 14 18 1 2 3 23 24 Lamp wattage was 36 W, correlated colour temperature 3000 K and general colour rendering index 1B. In the first phase commercially available electronic ballasts were tested and also 3 different ones in which the cathode heating was modified. When a lamp is dimmed, the current through the lamp decreases and without any actions the electrode temperature would decrease. The electrode temperature is maintained by an additional heating current through the electrode. The total current is the sum of discharge current and
heating current as Figure 3 shows.
Ballasts were made and modified by Helvar. As a reference there was one group with conventional magnetic ballasts (1) and one group with electronic ballasts from other manufacturer (3). In modified ballasts the heating current to cathodes had been modified to -10 %, +10 % or +20 % of the current of regular ballasts. Lamps were burned undimmed. The burning cycle was three hours, after each 2 hours 45 minutes of burning there were 15-minute breaks.
Figure 3. In dimming use the temperature of the electrode is maintained with heating current.
5
2 Methods In the second phase lamps were burned dimmed in a three-hour burning cycle and the dimming levels were 1 %, 5 % and 15 %. The cathode heating currents were the same as in Phase 1. The luminous fluxes of lamps in groups 7… 18 (Phase 2) were measured with reference ballast and after that lamps were dimmed individually for the test rack. The dimming level of an individual lamp with electronic ballast was 1 %, 5 % or 15 % from the value measured with reference ballast. When a lamp was inside the integrating sphere, a precision potentiometer was used to dim the lamp. Then the resistance of the potentiometer was measured and it was transferred to a trimmer after the luminous flux measurement. With the appropriate value of resistance, there is a suitable voltage (between 0… 10 V) over the trimmer that dims the lamp. After dimming, the lamp and the electronic ballast were installed as a couple in the test rack. In the third phase lamps were dimmed dynamically. The objective of the third phase was to find out the lamp life in a case where lamps were continuously dimmed, simulating different daylight situations. The whole cycle in Dynamic 1 was 175 minutes or 2 hours 55 minutes. The dimming levels were 100 %, 75 %, 50 %, 25 %, 15 % and 5 %. The dimming from one level to another lasted two and a half minutes. After the dimming period the lamps were burned 10 minutes on a certain level. There were two off-periods during one
cycle, one off-period was 10 minutes, Figure 4.
In Dynamic 2 one cycle was 250 minutes or 4 hours 10 minutes. The dimming levels were 100 %, 75 %, 50 % and 25 %. The dimming from one level to another lasted five minutes and after that the lamps were burned 20 minutes on a certain level. There were two off-
periods during one cycle, one off-period was 20 minutes, Figure 4.
In Dynamic 3 one cycle was also 250 minutes. The dimming levels were 100 %, 75 %, 50 % and 25 %. The difference from Dynamic 2 was, that there were no off-periods. Instead of breaks, lamps were burned 20 minutes on 25 % dimming level and 20 minutes on 100 % level. The dimming from one level to another lasted five minutes and after that
Table 2. Burning cycles in Dynamic 1, 2 and 3.
Duration of one cycle Breaks during one cycle Duration of a break Burning hours during one cycle Phase 1 and 2 3 h 1 15' 2 h 45' Dyn 1 2 h 55' 2 10' 2 h 35' Dyn 2 4 h 10' 2 20' 3 h 30' Dyn 3 4 h 10' 0 4 h 10' Relative amount of breaks during burning hours 1 2.1
1.6
The relative amount of breaks (switch-offs) during burning hours has been marked as 1 in
the three-hour burning cycle in Table 2. In Dynamic 1 there were 2.1 times more switch-
offs and in Dynamic 2 1.6 times more switch-offs than in the three-hour burning cycle. In Dynamic 3 there were no switch-offs.
In Figure 4 the rated burning cycles are with solid lines and the measured burning cycles
with dashed lines. Measurement was done with one lamp and ballast. The lamp was burning in an integrating sphere and the control voltage was taken from the test rack. Light 6
2 Methods output was measured with an illuminance sensor, which was connected to a data logger. The temperature inside the sphere depended on the dimming level. The temperature was between 22 ° C and 25 ° C. With the used lamp and ballast combination the luminous fluxes were 3… 8 % higher than the rated values. The time spent on one dimming level and the shift from one level to another were exactly as planned. Dynamic 1 100% 80% 60% 40% 20% 0% 0 50 100 150 Time / min 200 250 300 Dyn 1 Meas.
Dynamic 2 100% 80% 60% 40% 20% 0% 0 50 100 150 Time / min 200 250 300 Dyn 2 Meas.
Dynamic 3 100% 80% 60% 40% 20% 0% 0 Dyn 3 Meas.
50 100 150 200 250 300 Time / min
Figure 4. Burning cycles in Dynamic 1, 2 and 3. Solid lines show the rated burning cycles and dashed lines are measured burning cycles.
2.2 Photometric and electrical measurements
Photometric and electrical measurements were made after specific burning hours, that is, after 100, 1000, 2000, 4000, 8000 and 12 000 burning hours. The lamp life test was continued after the last measurement. 7
2 Methods The auxiliary in electrical and photometric measurements was reference ballast. Before the first measurements, lamps were aged 100 hours. Lamps were first burned in pre-warming rack for the minimum of 28 minutes and then moved into an integrating sphere. The stabilisation period was 7 minutes in the integrating sphere. The diameter of the sphere is 190 cm. The spectrometer was Labsphere´s DAS-2000. The spectrometer measures the spectral power distribution of the test lamp and compares it to the reference lamp. The spectrometer is connected to a PC, which then calculates the luminous flux and colour properties of the test lamp.
Figure 5. Integrating sphere used for photometric measurements.
Supply voltage was fed through voltage stabiliser. During the measurements the voltage was stable within ± 0.1 % of the rated voltage of the reference ballast. The rated voltage was 220 V. The harmonic content was less than 1%, defined as the r.m.s. summation of the individual components divided by the fundamental. Temperature inside the integrating sphere during measurements was 25 ± 2 ° C. Tempera ture was measured with thermocouple from the vertical midpoint near the surface of the sphere. The measured quantities were U P v tot supply I current total power including lamp power and losses of reference ballast P l lamp Φ η CCT luminous flux measured with reference ballast luminous efficacy Φ/Ptot correlated colour temperature Ra T amb general colour rendering index temperature inside the sphere. 8
2 Methods Groups 7… 18 were burned with dimmable electronic ballasts. When lamps were measured with electronic ballast, the stabilisation period was 12 minutes in the integrating sphere. The lamps were burned in pre-warming rack, but not the electronic ballasts. When lamps were dimmed to 1 %, 5 % or 15 % of the luminous flux with reference ballast, the resistance of the potentiometer and trimmer and cold spot temperature of the lamp were also measured. Φ dim luminous flux calculated as 1 %, 5 % or 15 % from the value measured with reference ballast Φ Φ R x% pot measured luminous flux when dimmed to 1 %, 5 % or 15 % from the value measured with reference ballast Φ Resistance R trim lamp Resistance Rpot was transferred to trimmer after the luminous flux measurement T L lamp temperature measured from the cold spot of the lamp when lamps were dimmed and were in the integrating sphere.
2.3 Blackening
When a lamp is ageing, the tube ends near the cathodes blacken. The blackening is caused by emitter material from the electrodes. Most of the material is likely to be tungsten, but it can also be barium. After 12 000 burning hours the blackening of lamps was evaluated subjectively. The blackening near the electrodes was evaluated by the tone value of the blackness, its width and also it was notified if there were layers. The tone of blackness was evaluated with a scale from 1 to 5, where 1 was clear, 2 light grey, 3 grey, 4 dark grey and 5 black. The width was given a letter A (0… 20 mm), B (21… 40 mm) or C (> 41 mm). If there were layers, it was marked with X. Researcher evaluated the tone of blackness. The researcher compared the test lamp to a bunch of lamps. The comparison lamps had four to five lamps on every tone value of blackness. 9
3 Results
3 Results
3.1 Lumen maintenance
Lumen maintenance was calculated from the reference value 3250 lm. This was deviation from the normal practice, in which the lumen maintenance is calculated from the value measured after 100 burning hours. Initially there were fifteen lamps in each test group. The lumen maintenance is an average of the lamps still alive. Mortalities of different test
3.1.1 Phase 1 – Undimmed
In Table 3 there is lumen maintenance of Phase 1 after 12 000 burning hours. In Phase 1
the burning cycle was three hours (2 h 45 min three lamps from each manufacturer. ON and 15 min OFF ) and lamps were burned undimmed. Lumen maintenance was calculated from the reference value 3250 lm. Cathode heating current levels were nominal (N) and -10 %, +10 % and +20 % from the nominal. In addition there was one group with magnetic ballasts and one with electronic ballasts from other manufacturer. In each test group there were lamps from five different manufacturers, There were variations between different test groups and also between different manufacturers in one test group. When compared different cathode heating levels, the lumen maintenance was highest on +10 % and +20 % cathode heating levels, the +10 % level being slightly better. When the cathode heating level was nominal, the lumen maintenance was 1.4
…2 percentage unit smaller compared to the +10 % level. On the –10 % level the lumen maintenance was smaller than on the other levels, but it was due to the non-functioning of B, C and D lamps. The lumen maintenance of A and E lamps on –10 % cathode heating level, that were still alive, was slightly smaller than on the nominal level. There were also differences between different manufacturers. The highest lumen maintenance was with D lamps and the lowest with E lamps. Phase 1 Group Nos.
A B C D E All
maintenance was calculated from the reference value 3250 lm. The plain figure after the percentage value is the number of lamps that are still alive after 12 000 burning hours.
N 2 92.9% /3 91.9% /3 89.0% /3 94.5% /3 87.4% /3 91.1% /15 Cathode heating level -10 % +10% 4 92.6% /2 /0 5 94.3% /3 93.3% /3 /0 /0 86.4% /3 88.9% /5 90.9% /3 96.5% /3 86.7% /3 92.3% /15 +20% 6 93.7% /3 93.4% /3 91.4% /3 95.0% /3 86.3% /3 92.0% /15 Magnetic Electronic 1 93.6% /3 91.2% /3 90.0% /3 96.1% /3 86.1% /3 91.4% /15 3 95.1% /3 92.9% /3 90.7% /3 94.6% /3 87.5% /3 92.1% /15 10
3 Results In addition to the four cathode heating levels, there were two other groups in Phase 1. In group 1 the ballast was conventional magnetic and in group 3 it was electronic ballast from another manufacturer. With the magnetic ballasts the lumen maintenance was better than with nominal heating level, but not as good as with +10 % and +20 % cathode heating levels. With the other electronic ballast the lumen maintenance was about the same as with +10 % cathode heating level.
3.1.2 Phase 2 – Static dimming
In Phase 2 the burning cycle was three hours (2 h 45 min number of lamps that are alive after 12 000 burning hours. OFF and 15 min ON ) and lamps were burned on 1 %, 5 % or 15 % luminous flux dimming level. Lumen maintenance was
calculated from the reference value 3250 lm. Table 4 shows the effect of dimming level on
the lumen maintenance. On each dimming level there were four different cathode heating levels. For instance in the second column, there were the undimmed test groups 2, 4, 5, 6. In these groups the cathode heating levels were nominal and -10 %, +10 % and +20 % of the nominal. Without dead lamps, the lumen maintenance values of different dimming levels would have been an average of sixty lamps, considering the dead lamps, it was an average of 39 to 50 lamps. The plain figure in the table after the percentage value is the When the luminous flux was dimmed to 1 %, 5 % and 15 % levels, the lumen maintenances were 96.4 %, 94.0 % and 91.8 %, respectively. When lamps were burned undimmed (100 % level from Phase 1), the lumen maintenance was 91.5 %.
Table 4. Lumen maintenance of different test groups after 12 000 burning hours. Lamps were burned undimmed and dimmed to 1 %, 5 % and 15 %.
Phase 2 Group Nos.
100 % 2,4,5,6 Luminous flux dimming level 1 % 5 % 7,8,9,10 11,12,13,14 15 % 15,16,17,18 A B C D 93.5% /11 92.9% /9 90.4% /9 95.3% /9 97.6% /11 96.5% /8 95.5% /10 96.0% /9 96.8% /8 94.1% /9 94.5% /6 91.2% /11 95.6% /4 93.1% /9 92.8% /8 87.5% /9 E 86.7% /12 96.2% /12 94.5% /12 92.1% /9 All 91.5% /50 96.4% /50 94.0% /46 91.8% /39 When lamps are burned dimmed, the discharge current through the lamp is smaller. When lamps were burned undimmed (the dimming circuit open), the total current was on the average 190 mA. Total current means the sum of the discharge current and the heating current through the electrode. When the luminous flux was dimmed to 1 %, 5 % and 15 %, the total currents were 79 mA, 87 mA and 97 mA, respectively. The total current was measured before the electronic ballast, the current was 50 Hz AC. The high frequency heating current through the electrode was about 320 mA in the undimmed test group and 570 …590 mA in the dimmed test groups.
In Table 5 on each cathode dimming level there were three test groups. For example with
nominal cathode heating level (N), there were test groups 7, 11 and 15, whose luminous fluxes had been dimmed to 1 %, 5 % and 15 %, respectively. There were dead lamps on every cathode heating level. 11
3 Results The nominal and +10 % cathode heating levels were slightly better than the cathode heating levels -10 % and +20 %. The lumen maintenance on nominal cathode heating level was 94.7 % and with +10 % level 94.5 %. On -10 % level the maintenance was 93.9 % and on +20 % level 93.6 %.
maintenance was calculated from the reference value 3250 lm.
Phase 2 Group Nos.
N 7,11,15 Cathode heating level -10 % 8,12,16 +10% 9,13,17 +20% 10,14,18 A B C D 97.4% /7 95.2% /9 94.6% /9 92.5% /9 97.1% /4 /0 95.1% /1 90.5% /4 96.7% /7 94.4% /8 94.6% /9 92.5% /8 96.7% /5 93.9% /9 93.3% /5 90.0% /8 E 94.2% /9 93.9% /8 94.7% /9 95.2% /7 All 94.7% /43 93.9% /17 94.5% /41 93.6% /34 The lumen maintenances of Phase 2 were better than that of Phase 1. One exception was D lamps. Their maintenances on Phase 1 were 94.5 %, 96.5 % and 95.0 % with cathode heating levels nominal, +10 % and + 20 %. In Phase 2 maintenances were 92.5 %, 92.5 % and 90.0 % with same cathode heating levels. The lumen maintenances of E lamps were high, when compared to E lamps in Phase 1.
3.1.3 Phase 3 – Dynamic dimming
Phase 3 - the dynamic dimming was started later than phases 1 and 2 according to the achieved results. In the phase 3 there were only two cathode heating levels, namely the nominal and the +20 % heating level. Results of Phase 3 after 12 000 burning hours are in
Table 6. Lumen maintenances of different dynamic dimming levels after 12 000 burning hours.
Phase 3 Cathode heating level N/+20% N/+20% N/+20% Group Nos.
Dynamic 1 Dynamic 2 Dynamic 3 A B C D 92.9 % /6 91.7 % /6 92.4 % /3 86.8 % /5 92.6 % /5 91.6 % /6 91.9 % /6 85.9 % /6 94.1 % /6 93.2 % /6 93.5 % /4 91.1 % /6 E 89.9 % /6 88.3 % /6 89.2 % /6 All 90.7 % /26 90.0 % /29 92.1 % /28 The lumen maintenance was the highest in Dynamic 3. The lumen maintenance was 92.1 % in Dynamic 3, 90.0 % in Dynamic 2 and 90.7 % in Dynamic 1. The only difference between Dynamic 2 and 3 was, that there were no breaks in Dynamic 3. When the relative amount of breaks during burning hours of standard 3 hour burning cycle was 1, in 12
3 Results Dynamic 1 it was 2.1 and in Dynamic 2 1.6. A further difference between Dynamic 1 and 2 is that there were more luminous flux dimming levels in Dynamic 1 and the dimming from one level to another lasted 2.5 minutes in Dynamic 1 and 5 minutes in Dynamic 2. The
dynamic dimming levels are described in Table 2 and in Figure 4.
Table 7 shows the effect of cathode heating level when lamps are dimmed dynamically. On
both cathode heating levels there are three test groups, which have been driven with Dynamic 1, 2 and 3. On nominal heating level there were two dead lamps and on +20 % level five dead lamps after 12 000 burning hours. On nominal cathode heating level the lumen maintenance was 91.4 % and on +20 % level it was 90.5 % after 12 000 burning hours.
Table 7. Lumen maintenances with dynamic dimming on cathode heating levels nominal and +20 % after 12 000 burning hours.
Phase 3 Group Nos.
A B C D E All Cathode heating level N +20% 19,21,23 20,22,24 93.2 % /9 93.3 % /8 92.2 % /9 92.8 % /8 89.3 % /8 89.3 % /9 91.4 % /43 92.1 % /9 92.2 % /5 86.9 % /9 89.0 % /9 90.5 % /40
3.1.4 All test groups
Table 8 shows lumen maintenances of all the 24 different test groups measured after
12 000 burning hours. In Phase 1 lamps were burned undimmed, in Phase 2 lamps were dimmed to 1 %, 5 % or 15 % and in Phase 3 lamps were dimmed dynamically.
Table 8. Lumen maintenance of different test groups after 12 000 burning hours.
Dimming level Phase 1 100 %, magnetic ballast 100 %, Helvar EL 1x36 HF 100 %, electronic ballast Phase 2 1 % 5 % 15 % All Phase 3 Dynamic 1 Dynamic 2 Dynamic 3 nominal 91.4% 91.1% 92.1% 96.9% 94.7% 92.1% 94.7% 91.2% 90.1% 92.7% Cathode heating –10% +10% 88.9% 95.9% 94.1% 89.4% 93.9% 92.3% 97.0% 94.0% 92.5% 94.5% +20% 92.0% 95.4% 93.1% 90.7% 93.6% 90.2% 89.8% 91.4% All 91.4 % 91.5 % 92.1 % 96.4 % 94.0 % 91.8 % 94.3 % 90.7 % 90.0 % 92.1 % All 91.4 % 90.5 % 90.9 %
Table 9 shows that the average of lumen maintenances of 268 measured lamps after 12 000
burning hours was 92.7 %. The lumen maintenance of the undimmed test groups or Phase 1 was 91.5 %. The lumen maintenance of the static dimming test groups or Phase 2 was 13
3 Results 94.3 % and the lumen maintenance of the dynamic dimming test groups or Phase 3 was 90.9 %. The lamps with magnetic ballasts and with other electronic ballasts were burned undimmed and their lumen maintenances were 91.4 % and 92.1 %, respectively.
Table 9. Lumen maintenances of different phases after 12 000 burning hours. After the percentage is the number of lamps alive.
Group Nos.
A B C D E All All 2,4,5… 23,24 95.0% /51 93.4% /53 93.1% /46 91.1% /55 91.5% /63 92.7% /268 Phase 1 2,4,5,6 93.5% /11 92.9% /9 90.4% /9 95.3% /9 86.7% /12 91.5% /50 Phase 2 Phase 3 7,8,… 17,18 19,20,… 23,24 97.0% /23 93.2% /17 94.5% /26 94.4% /24 91.5% /29 92.2% /18 92.5% /13 88.0% /17 94.5% /33 89.1% /18 94.3% /135 90.9% /83 Magnetic Electronic 1 3 93.6% /3 95.1% /3 91.2% /3 90.0% /3 96.1% /3 86.1% /3 91.4% /15 92.9% /3 90.7% /3 94.6% /3 87.5% /3 92.1% /15
3.2 Mortality 3.2.1 Phase 1 – Undimmed
The mortalities of Phase 1 after 12 000 burning hours are in Table 10. After 12 000
burning hours there were dead lamps only on -10 % cathode heating level. In this group 67 % of lamps were not functioning. Only two lamps had broken cathode, eight lamps were not dead, but after 200… 2000 hours of burning they did not start with the used electronic ballast. However, the cathode was not broken and they started for instance with conventional magnetic ballast, therefore the emission material of cathodes was not finished. So the conclusion was that the reason for not switching on was the low cathode heating current on starting. However, these lamps are included in the following tables as dead lamps.
Table 10. Mortalities of Phase 1 after 12 000 burning hours. Initially in each test group there were fifteen lamps, three lamps from each manufacturer.
Phase 1 Group Nos.
N 2 Cathode heatin g level -10 % 4 +10% 5 +20% 6 Magnetic Electronic 1 3 A B C 0 % 0 % 0 % 33 % 100 % 100 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % D E 0 % 0 % 100 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % 0 % All 0 % 67 % 0 % 0 % 0 % 0 %
Figure 6 shows the mortality curves of the undimmed test groups in Phase 1. On cathode
heating levels +10 % and +20 % there were no dead lamps even after 25 000 burning hours. In addition to the electronic ballasts with different cathode heating levels, in Phase 1 there was also one test group with conventional magnetic ballasts and one test group with other electronic ballasts. 14
3 Results Effect of ballast on mortality 100 % 80 % 60 % 40 % 20 % B N EL 0 % 0 5000 10000 15000 Burning hours 20000 25000 30000
Figure 6. Mortality curves of Phase 1. B is magnetic ballast, N electronic ballast with nominal cathode heating level and EL is electronic ballast from another manufacturer.
3.2.2 Phase 2 – Static dimming
Table 11 shows the mortalities of the dimmed test groups after 12 000 burning hours. On
each dimming level there were four test groups or sixty lamps, twelve lamps from each manufacturer. Dimming had the strongest effect on mortality on the 15 % luminous flux level. On that level the mortality was 35 %. On 5 % and 1 % luminous flux levels, the mortalities were 23 % and 17 %, respectively. On 100 % luminous flux level the mortality was the same as on 1 % level, or 17 %. Lamps were burned undimmed also with magnetic ballast and with an electronic ballast from other manufacturer. In these test groups there
were no dead lamps after 12 000 burning hours (Table 10).
Manufacturer E had dead lamps only on the 15 % luminous flux dimming level, on that level the mortality of E was 25 %. When looking the highest mortality on different luminous flux dimming levels by manufacturer, A had 67 % mortality on the 15 % dimming level, B 33 % mortality on the 1 % level, C 50 % mortality on 5 % level, D 25 % mortality on 100 %, 1 % and 15 % dimming levels and E 25 % mortality on 15 % dimming level.
Table 11. Effect of dimming on mortality after 12 000 burning hours.
Group Nos. A B C D E All Luminous flux dimming level 100 % 1 % 5 % 15 % 2,4,5,6 7,8,9,10 11,12,13,14 15,16,17,18 8 % 8 % 33 % 67 % 25 % 25 % 25 % 0 % 17 % 33 % 17 % 25 % 0 % 17 % 25 % 50 % 8 % 0 % 23 % 25 % 33 % 25 % 25 % 35 % 15
3 Results
Table 12 shows the mortality of different cathode heating levels. On each cathode heating
level there were three test groups or forty-five lamps. On the nominal cathode heating level, there were only 2 dead lamps out of 45, so the mortality was 4 %. On the +10 % level, mortality was 9 %. The +20 % and -10 % levels were clearly worse, mortalities were 24 % and 62 %. Manufacturer E had the smallest mortality after 12 000 burning hours, mortality was 8 %. E lamps were long-life lamps and the rated lamp life given by the manufacturer is 36 000 hours, about three times the rated lamp life of other manufacturers. All manufacturers except E had high mortality on -10% cathode heating level. On nominal and +10 % levels, mortalities were low. On +20 % cathode heating level A and C had 44 % mortality and E 22 %.
Table 12. Effect of cathode heating on mortality of Phase 2 after 12 000 burning hours.
Phase 2 Group Nos.
N 7,11,15 Cathode heating level -10 % 8,12,16 +10% 9,13,17 +20% 10,14,18 A B C D E 22 % 0 % 0 % 0 % 0 % 56 % 100 % 89 % 56 % 11 % 22 % 11 % 0 % 11 % 0 % 44 % 0 % 44 % 11 % 22 % All 4 % 62 % 9 % 24 %
Figure 7 shows the mortality curves of different cathode heating levels. Different luminous
flux dimming levels are combined in the same curve. Effect of cathode heating on mortality 100 % 80 % 60 % 40 % 20 % N -10 % +10 % +20 % 0 % 0 5000 10000 15000 Burning hours 20000 25000 30000
Figure 7. Mortality of Phase 2. On every cathode heating level (nominal N, -10 %, +10 % and +20 % from nominal) there were 45 lamps. The luminous fluxes of the lamps were dimmed to 1 %, 5 % or 15 %.
16
3 Results
Figure 8 shows the mortality curves of different luminous flux dimming levels. Different
cathode heating levels are combined in the same curve. Effect of dimming on mortality 100 % 80 % 60 % 40 % 20 % 1 % 5 % 15 % 100 % 0 % 0 5000 10000 15000 20000 Burning hours 25000 30000
Figure 8. Mortality of Phase 2. On dimming levels 1 %, 5 %, 15 % there were 60 lamps respectively, on the undimmed level there were 45 lamps. The cathode heating levels in the dimmed groups were nominal, -10 %, +10 % and +20 %, in the undimmed test groups the -10 % cathode heating level was not included.
3.2.3 Phase 3 – Dynamic dimming
Table 13 shows the mortality of Phase 3 after 12 000 burning hours. On every dynamic
dimming level there were two test groups or thirty lamps. There were four dead lamps in Dynamic 1, one dead lamp in Dynamic 2 and two dead lamps in Dynamic 3.
Table 13. Effect of dynamic dimming on mortality after 12 000 burning hours.
Phase 3 Cathode heatin g level N/+20% N/+20% N/+20% Dimming Dynamic 1 Dynamic 2 Dynamic 3 A B C D 0 % 0 % 50 % 17 % 17 % 0 % 0 % 0 % 0 % 0 % 33 % 0 % E 0 % 0 % 0 % All 13 % 3 % 7 %
Table 14 shows that two dead lamps had nominal cathode heating level and five lamps had
+20 % heating level. On both cathode heating levels there were three test groups or forty five lamps. One of the dead lamps was from manufacturer A, five from C and one from D. 17
3 Results
Table 14. Mortalities with dynamic dimming on cathode heating levels nominal and +20 % after 12 000 burning hours.
Phase 3 Cathode heating level N +20% Group Nos.
A 19,21,23 0 % 20,22,24 11 % B C 0 % 11 % 0 % 44 % D E 11 % 0 % 0 % 0 % All 4 % 11 %
Figure 9 shows the effect of cathode heating on mortality, when lamps were dimmed
dynamically. On both cathode heating levels there were fifteen lamps in Dynamic 1, Dynamic 2 and Dynamic 3. Effect of cathode heating on mortality 100 % 80 % 60 % 40 % 20 % N +20% 0 % 0 5000 10000 15000 20000 Burning hours 25000 30000
Figure 9. Mortality of Phase 3. On both cathode heating levels there were 45 lamps. Lamps were dimmed dynamically.
Figure 10 shows the effect of dynamic dimming on mortality. There were no breaks in
Dynamic 3. The relative amount of breaks in Dynamic 1 was 2.1 and in Dynamic 2 1.6
compared to three hour burning cycle. The dynamic burning cycles are in Figure 4.
18
3 Results Effect of dynamic dimming on mortality 100 % 80 % 60 % 40 % 20 % Dyn 1 Dyn 2 Dyn 3 0 % 0 5000 10000 15000 20000 25000 30000 Burning hours
Figure 10. Mortality of Phase 3. On every dynamic dimming drive there were thirty lamps. Cathode heating levels were nominal and +20 %.
3.2.4 All test groups
Table 15 shows that the mortality of the five manufacturers, 22 test groups and 330 lamps
after 12 000 burning hours was 19 %. In the second column (All) the magnetic ballast test group or the other electronic ballast test group is not included. The mortality of the undimmed test groups or Phase 1 was 17 %. The mortality of the static dimming test groups or Phase 2 was 25 % and the mortality of the dynamic dimming test groups or Phase 3 was 8 %. The lamps with magnetic ballasts and with other electronic ballasts were burned undimmed and there were no dead lamps in these test groups after 12 000 burning hours.
Table 15. Mortality of lamps in different Phases and by different manufacturers after 12 000 burning hours. After the percentage is the number of lamps initially.
All Phase 1 Phase 2 Phase 3 Magnetic Electronic Group Nos.
A B C D 2,4,5… 23,24 23 % /66 20 % /66 30 % /66 17 % /66 2,4,5,6 8 % /12 25 % /12 25 % /12 25 % /12 7,8,… 17,18 19,20,… 23,24 36 % /36 28 % /36 33 % /36 19 % /36 6 % /18 0 % /18 28 % /18 6 % /18 1 0 % /3 0 % /3 0 % /3 0 % /3 3 0 % /3 0 % /3 0 % /3 0 % /3 E 5 % /66 0 % /12 8 % /36 0 % /18 0 % /3 0 % /3 All 19 % /330 17 % /60 25 % /180 8 % /90 0 % /15 0 % /15
Table 16 shows the mortalities of different test groups after 8000, 12 000, 15 000 and
18 000 burning hours. Initially in each test group there were fifteen lamps: three lamps from five manufacturers. 19
3 Results
Table 16. Mortalities of different test groups after 8000, 12 000, 15 000 and 18 000 burning hours. In each test group there were fifteen lamps initially.
8 000 burning hours
Phase 1 100 %, magnetic ballast 100 %, Helvar EL 1x36 HF 100 %, electronic ballast Phase 2 Phase 3 1 % 5 % 15 % Dynamic 1 Dynamic 2 Dynamic 3
12 000 burning hours
Phase 1 100 %, magnetic ballast 100 %, Helvar EL 1x36 HF 100 %, electronic ballast Phase 2 1 % 5 % Phase 3 15 % All Dynamic 1 Dynamic 2 Dynamic 3 All
15 000 burning hours
Phase 1 100 %, magnetic ballast 100 %, Helvar EL 1x36 HF Phase 2 100 %, electronic ballast 1 % 5 % 15 % Phase 3 All Dynamic 1 Dynamic 2 Dynamic 3 All nominal 0 % 0 % 0 % 0 % 0 % 0 % 7 % 0 % 0 % 7 % 0 % 0 % 7 % 7 % 13 % 9 % 13 % 13 % 0 % 9 % 0 % 0 % 0 % 0 % 7 % 7 % 4 % 13 % 0 % 0 % 4 % Cathode heating –10% +10% 67 % 53 % 27 % 60 % 67 % 60 % 47 % 80 % 62 % 67 % 60 % 47 % 87 % 64 % 0 % 0 % 0 % 7 % 0 % 7 % 13 % 7 % 9 % 0 % 7 % 13 % 13 % 11 % +20% 0 % 0 % 13 % 20 % 0 % 0 % 7 % 0 % 0 % 27 % 47 % 24 % 13 % 7 % 13 % 11 % 0 % 0 % 27 % 53 % 27 % 13 % 7 % 13 % 11 % All 17 % 13 % 10 % 22 % 3 % 0 % 3 % 17 % 17 % 23 % 35 % 13 % 3 % 7 % 17 % 18 % 23 % 42 % 13 % 10 % 7 % All Phase 11 % 15 % 2 % 11 % 25 % 8 % 12 % 28 % 10 %
18 000 burning hours
Phase 1 100 %, magnetic ballast 100 %, Helvar EL 1x36 HF Phase 2 100 %, electronic ballast 1 % Phase 3 5 % 15 % All Dynamic 1 Dynamic 2 Dynamic 3 20 % 13 % 0 % 7 % 20 % 27 % 18 % 47 % 33 % 0 % 73 % 67 % 47 % 87 % 67 % 0 % 20 % 13 % 13 % 16 % 0 % 0 % 33 % 53 % 29 % 33 % 7 % 13 % 22 % 23 % 28 % 45 % 40 % 20 % 7 % 18 % 32 % 22 % All 27 % 18 % After 12 000 burning hours the mortality was slightly higher in the dimmed test groups than in the undimmed groups. With the nominal cathode heating level there were no dead 20
3 Results lamps in the undimmed test groups. In the static dimming groups there was one dead lamp from dimming groups 5 % and 15 %, respectively. In the Dynamic 1 there were two dead lamps, but no dead lamps in Dynamic 2 or 3 with nominal cathode heating level. With the nominal and +10 % cathode heating levels the mortality was only 0… 13 % after 15 000 burning hours. The mortality was higher on the static dimming test groups than in the dynamic dimming test groups. With static dimming the cathode heating levels N and +10 % showed the lowest mortality, only 18 % and 16 %, respectively, after 18 000 burning hours.
3.3 Blackening
The blackening near the electrodes was evaluated by the tone value of the blackness, its width and also it was notified if there were layers. As an example there is test group 11, where the cathode heating level of the ballast was nominal and the dimming level was 5 %.
Table 17 shows the average lumen reduction of different manufacturers´ lamps and the
evaluation of the blackness. The lumen reduction was calculated from the measured initial luminous flux, that is, luminous flux after 100 burning hours. There were three lamps from every manufacturer.
Table 17. Subjective evaluation of the blackening of the lamps in test group 11.
No of the lamp Manuf. Lamp end 1 and Blackness reduc.
B L W B Lamp end 2 Blackness L W 10 11 12 13 14 1 2 3 4 5 6 7 8 9 A 3.9 % B 4.2% C 3.3% D 0.7% E 2 1 2 1 3 2 2 2 1 1 1 1 1 X X A A A A A A A A A A A A A 2 2 2 2 3 3 1 2 1 2 1 1 1 X X X A A A A A A A A A A A A A 15 4.6% 1 A 2 X A B L Blackness 1: clear, 2: light grey, 3: grey, 4: dark grey, 5: black Layers W Width X: layers exist A: 0… 20 mm, B: 21… 40 mm, C:> 41 mm Even though the blackness was quite evident with manufacturers B and C and there were already black layers near the ends of the tubes, the lumen reduction was still moderate.
Table 18 shows the average of blackness of different test groups. In the table there is the
blackness of both ends. In each test groups there were fifteen lamps initially. 21
3 Results
Table 18. Evaluation of blackness of different test groups after 12 000 h.
100 %, magnetic ballast 100 %, Helvar EL 1x36 HF 100 %, electronic ballast 1 % 5 % 15 % Dynamic 1 Dynamic 2 nominal 2.1
1.9
1.5
1.9
1.7
1.5
1.6
1.5
1.5
1.8
2.1
1.4
1.4
1.6
1.5
1.5
2.0
1.2
1.1
1.3
Cathode heating –10% +10% 1.6
1.5
1.4
1.0
1.6
1.5
1.8
1.3
1.5
1.5
1.6
1.4
1.9
1.8
2.0
2.4
1.4
1.4
+20% 1.5
1.7
2.0
2.3
1.9
1.8
All 1.7
1.6
1.7
1.7
1.6
1.5
Dynamic 3 1.3
1.1
1.6
1.2
1.3
Table 19 shows the blackness of different manufacturers´ lamps sorted by the cathode
heating level and by the luminous flux dimming level. Phase 3 had only cathode heating levels nominal and +20 % and therefore lamps of Phase 3 were not included in the table.
Table 19. Evaluation of blackness of lamps in Phase 1 and 2 after 12 000 burning hours.
Manufacturer A B C D E All Manufacturer A B C D E All nominal 1.9 /1.8
1.8 /1.5
1.6 /2.8
1.6 /1.1
1.6 /1.1
1.7
100 % 2.2 /1.8
1.4 /1.1
1.7 /2.8
1.6 /1.0
1.7 /1.1
1.6
Cathode heating –10% +10% 1.7 /2.0
1.5 /1.9
1.5 /1.7
1.0 /2.0
1.3 /1.3
1.3 /1.1
1.4
1.8 /1.8
1.1 /1.1
1.8 /1.1
1.5
Luminous flux dimming level 1 % 5 % 1.5 /1.9
1.8 /1.6
1.6 /2.1
2.3 /2.2
1.6 /2.2
1.2 /1.1
1.8 /1.1
1.6
2.0 /2.0
1.1 /1.5
1.5 /1.1
1.7
+20% 2.0 /2.0
2.4 /2.2
2.4 /2.5
1.3 /1.5
1.9 /1.0
1.9
15 % 1.5 /1.8
2.1 /2.2
2.3 /2.1
1.4 /1.1
1.6 /1.0
1.7
All 1.8
1.8
2.1
1.3
1.3
1.6
1.8
1.8
2.1
1.3
1.3
1.6
All
3.4 CCT and Ra
Correlated colour temperature and colour rendering index were measured at the same time as luminous fluxes. Their values in different test groups after 100 and 12 000 burning
hours are in Table 20. In one test group there were lamps from five different
manufacturers. The rated value for colour temperature was 3000 K and for colour rendering index class 1B (80 ≤ Ra < 90). The correlated colour temperatures after 100 hours of burning were 3034 K… 3054 K, after 12000 hours 2974 K… 3054 K. The colour temperatures decreased a little, the largest drop was 80 K in 12 000 burning hours. There were little differences in colour temperatures between different manufacturers. The colour temperatures of A, B, C, D and E after 100 hours were 3091 K, 3053 K, 2964 K, 3004 K, 3102 K and after 12 000 hours 3050 K, 22
3 Results 3012 K, 2926 K, 2946 K and 3046 K. The shifts in colour temperatures were approxi mately the same with different manufacturers’ lamps. The variations between different manufacturers were larger than were the variations due to the burning of lamps.
Table 20. Correlated colour temperature and colour rendering index measured after 100 and 12 000 or 8000 burning hours.
100 %, magnetic ballast 100 %, Helvar EL 1x36 HF 100 %, electronic ballast 1 % 5 % 15 % Dynamic 1 Dynamic 2 Dynamic 3 Average Colour rendering index 100 %, magnetic ballast 100 %, Helvar EL 1x36 HF 100 %, electronic ballast 1 % 5 % 15 % Dynamic 1 Dynamic 2 85.0
85.0
85.0
84.8
84.8
84.9
85.1
85.1
Cathode heating nominal –10% +10% +20% 100 12000 100 12000 100 12000 100 12000 3049 2974 3047 2975 3048 3018 3054 2974 3044 2979 3046 2975 3038 3024 3037 3054 3046 3032 3035 3020 3041 3017 3044 3036 3037 3023 3044 3036 3047 2998 3053 3006 3047 3001 3052 2989 3035 2994 3036 2993 3035 2980 3034 2982 3036 2975 3036 2987 3041 2991 3046 3029 3046 3008 3040 2997 85.0
85.0
85.1
85.2
85.1
85.1
85.3
85.1
85.0
84.9
84.9
84.9
85.7
85.6
85.5
85.5
85.0
84.6
84.8
85.0
85.1
85.0
85.0
85.1
85.0
84.9
85.0
84.9
85.1
85.1
85.1
85.2
85.4
84.8
85.3
85.1
Dynamic 3 85.1
85.2
85.1
85.3
Average 85.0
85.1
84.9
85.6
84.9
85.1
85.0
85.2
The variations in colour rendering indices were insignificant. The average general colour rendering index of fifteen lamps was between 84.6 and 85.1 after 100 hours. The minimum general colour rendering index of an individual lamp was 80.6 and the maximum 86.1 after 100 burning hours. After 12 000 hours the minimum was 81.2 and the maximum 86.3. The average of colour rendering indices of different manufacturers were 85.7, 84.6, 84.0, 84.8 and 85.7 after 100 hours and 85.9, 84.9, 84.1, 85.0 and 85.7 after 12 000 hours. 23
4 Conclusions
4 Conclusions
When lamps were burned statically on low light levels, the lumen maintenance was higher compared to burning on full light level. When lamps were dimmed dynamically without breaks (Dynamic 3) the lumen maintenance was also higher than when lamps were burned on full light level. However, when lamps were dimmed dynamically and the switching cycle was 2.1 times or 1.6 times higher than the standard 3 hour burning cycle on full light level, then the lumen maintenance was little lower on the dynamic test groups. The difference in lumen maintenance was anyhow only one to two percentage unit. The effect of cathode heating level on lumen maintenance is negligible compared to the effect of dimming on lumen maintenance. The lumen maintenance after 12 000 burning hours showed: − In the undimmed test groups the differences due to manufacturers are bigger than due to different cathode heating levels. − If lamps are dimmed to low light levels (1 % and 5 %) statically, the lumen maintenance is higher than if lamps are burned undimmed. − The lumen maintenance of the dynamic dimming test groups does not differ much from the undimmed test groups. − The effect of breaks on the lumen maintenance is greater than the effect of dynamic dimming. Lamps can be burned continuously on low light levels and dim dynamically without the lumen reduction to cause lamp replacement. The cathode heating level had clear effect on lamp life. After 12 000 burning hours the mortalities of the static dimming groups were 62 % with –10 % cathode heating level, 4 % with nominal level, 9 % with +10 % level and 24 % with +20 % level. The mortalities of the dynamic dimming groups were 4 % with nominal cathode heating level and 11 % with +20 % level. Too small cathode heating current was more disastrous to the lamp life than was too large heating current was. When the cathode heating level was nominal or +10 %, the lamp life was long. After 15 000 hours the mortalities of different test groups were only 0… 13 %. The rated lamp life was 12 000 hours (30 % mortality). After 18 000 burning hours it can be seen that: − Mortalities were low with cathode heating levels N, +10 % and +20 %, when lamps were burned undimmed. − Mortalities were higher in the dimmed test groups than on the undimmed test groups. − Mortalities were lower on the 1 % and 5 % dimming levels than on the 15 % dimming level. − With static dimming the cathode heating levels N and +10 % showed the lowest mortalities, only 18 % and 16 %, respectively, after 18 000 burning hours. − With dynamic dimming the mortalities were lower with +20 % cathode heating than with nominal cathode heating. 24
4 Conclusions − Of the dynamic dimming test groups, the mortality was lowest in Dynamic 3, where there were no breaks. The blackening of the lamp ends was evaluated subjectively. The differences between lamps were quite small and most of the lamps were evaluated as clear or light grey. The subjective evaluation was not a good method to give results of small differences. A method without subjective evaluation would have been better. Such a method could be for instance a luminance measurement. Lamps can be burned continuously on low light levels and dim dynamically without affecting the lumen maintenance so much that it would shorten the economical lamp life. With proper cathode heating level the lamp will reach the nominal lamp life both if the lamp is dimmed statically or dynamically. The lamp or the electronic ballast is thus not an obstacle for wider use of daylight with artificial lighting. 25
5 Summary
5 Summary
The lumen maintenances after 12 000 burning hours of the static dimming test groups were higher than of the test groups that were burned undimmed. When the luminous flux was dimmed to 1 %, 5 % or 15 % levels, the lumen maintenances were 96.4 %, 94.0 % and 91.8 %, respectively. When lamps were burned undimmed (100 % level), the lumen maintenance was 91.5 %. With conventional magnetic ballasts, lumen maintenance was 91.4 % and with electronic ballasts from another manufacturer 92.1 %. With dynamic dimming the maintenances were 90.7 %, 90.0 % and 92.1 %. On average the maintenance of the undimmed test groups was 91.5 %, the static dimming test groups 94.3 % and the dynamic dimming test groups 90.9 %. When lamps are burned dimmed, the current through the lamp is smaller and this is the reason for better lumen maintenance of dimmed tests groups compared to undimmed groups. When lamps were burned undimmed (the dimming circuit open), the total current (50 Hz) was on the average 190 mA. When the luminous flux was dimmed to 1 %, 5 % and 15 %, the current was 79 mA, 87 mA and 97 mA, respectively. The dimmed test groups show that lamps can be burned on low dimming levels without affecting the lumen maintenance. On the contrary, when lamps were burned continuously on low dimming levels, the lumen reduction was smaller than when lamps were burned on full light level. Also in dynamic dimming the lumen maintenance was almost the same as when lamps were burned on full light level. On full light level (100 %), the lumen maintenances were the highest on +10 % and +20 % cathode heating levels, the +10 % level being a slightly better. When the cathode heating level was nominal, the lumen maintenance was 1.4… 2 percentage unit less compared to the +10 % level. It was difficult to evaluate the -10 % level, because there was only 5 lamps out of 15 that had survived the 12 000 burning hours. In the static dimming test groups the nominal cathode heating level seemed to be slightly better than the modified cathode heating levels -10 %, +10 % and +20 %. The +10 % level was also good. The lumen maintenance on nominal cathode heating level was 94.7 % and with +10 % level 94.5 %. On -10 % level the maintenance was 93.9 % and on +20 % level 93.6 %. In the dynamic dimming test groups the lumen maintenances were 91.4 % with nominal cathode heating and 90.5 % with +20 % cathode heating. Considering the lumen maintenance and the right cathode heating level, it seems that the heating level does not seem to have a severe effect on the lumen maintenance. Yet the nominal and +10 % levels are slightly better than the -10 % and +20 % levels. On the nominal cathode heating level the mortality was the lowest. After 12 000 burning hours mortality was zero in the undimmed test group and 7 % in the dimmed test groups. With +10 % cathode heating level mortality was 7 % on 1 % and 15 % luminous flux levels and 13 % on the 5 % level. On the -10 % cathode heating level the mortalities were the highest: 60 %, 47 % and 80 % on luminous flux dimming levels 1 %, 5 % and 15 % after 12 000 burning hours. 26
5 Summary Dimming had the strongest effect on mortality on the 15 % luminous flux level. On that level the mortality was 35 % after 12 000 burning hours. On 5 % and 1 % luminous flux levels, the mortalities were 23 % and 17 %, respectively. On 100 % luminous flux level the mortality was the same as on 1 % level, or 17 %. Lamps were burned undimmed also with magnetic ballast and with an electronic ballast from other manufacturer. In these test groups there were no dead lamps. The researcher evaluated the blackening near the electrodes subjectively by the tone value of the blackness, its width and also it was notified if there were layers. The blackening was a little darker in the dimmed test group than in the undimmed test group. Still, the lumen maintenance was higher in the dimmed test group. It seems that the additional heating current caused the blackening of the lamp ends. However, because the lumen reduction was smaller in the dimmed test groups, it can be concluded that in this case the blackening do not affect the characteristics or the functioning of the lamp. The variations of correlated colour temperature between different manufacturers were greater than were the variations due to the burning of lamps. The variations in colour rendering indices were insignificant. 27
6 References
6 References
Halonen L. 1997. The performance of intelligent lighting control systems (in Finnish). In: RAKET Research Seminar. pp. 37 - 46, 1997. Halonen L, Lehtovaara J. 1997. Study of a pilot control system based on data acquisition system. Helsinki University of Technology. Lighting Laboratory. 28
7 Appendices
7 Appendices
Appendix 1 Lumen maintenance and mortality for different test groups. Lumen maintenance is calculated from the reference value 3250 lm. Appendix 2 Example of the photometric and electrical measurements of group 01. Measurements were done after 100, 1000, 2000, 4000, 8000 and 12 000 burning hours. 29
Appendix 1 (1/4)
Lumen maintenance
Lumen maintenance is calculated from the reference value 3250 lm. Test Group 1 3 2 4 Elekt. Dim. Manufacturer flux B N 100 % A B C D E Average N,O 100 % A B C D E Average 100 % A B C D E Average -10 % 100 % A B C D E Average 100 100 1000 lumen † 101.6% 100.0% 0 99.4% 97.8% 97.4% 0 95.6% 0 97.3% 100.2% 0 98.9% 94.4% 0 99.0% 97.5% 0 101.1% 100.3% 0 98.9% 97.7% 0 97.4% 96.7% 96.0% 0 97.3% 0 99.9% 98.8% 95.7% 0 97.4% 0 101.0% 98.8% 97.6% 97.8% 99.8% 99.0% 99.2% 0 97.2% 0 95.6% 0 96.2% 0 95.9% 0 96.8% 0 101.2% 98.6% 97.1% 96.2% 98.5% 98.3% 98.8% 1 96.8% 0 96.5% 0 97.2% 0 94.3% 0 96.6% 1 Burning hours 2000 lumen † 99.0% 0 4000 lumen † 96.7% 0 96.5% 0 94.6% 0 94.4% 0 92.3% 0 99.7% 0 92.0% 0 96.4% 0 98.1% 0 90.7% 0 94.4% 0 98.8% 0 96.6% 0 95.3% 0 97.8% 0 93.8% 0 96.5% 0 97.5% 0 95.7% 0 93.9% 0 96.9% 0 93.5% 0 95.5% 0 96.7% 0 94.1% 0 92.6% 0 96.0% 0 92.1% 0 94.3% 0 96.3% 0 94.9% 0 93.0% 0 97.0% 0 91.7% 0 94.6% 0 8000 lumen † 94.2% 0 92.0% 0 90.3% 0 95.8% 0 87.6% 0 92.0% 0 94.5% 0 92.5% 0 90.3% 0 93.8% 0 89.6% 0 92.1% 0 93.3% 0 91.9% 0 89.7% 0 93.7% 0 89.2% 0 91.6% 0 12000 lumen † 93.6% 0 91.2% 0 90.0% 0 96.1% 0 86.1% 0 91.4% 0 95.1% 0 92.9% 0 90.7% 0 94.6% 0 87.5% 0 92.1% 0 92.9% 0 91.9% 0 89.0% 0 94.5% 0 87.4% 0 91.1% 0 97.7% 1 95.3% 1 92.8% 1 92.6% 1 94.7% 0 3 3 3 95.8% 0 3 3 3 97.2% 0 3 3 3 92.1% 0 95.3% 1 90.5% 0 92.4% 10 87.4% 0 89.6% 10 86.4% 0 88.9% 10 5 6 +10% 100 % A B C D E Average +20% 100 % A B C D E Average 100.3% 98.7% 97.4% 97.5% 99.3% 98.6% 99.5% 98.8% 97.5% 96.2% 98.6% 98.1% 99.2% 0 97.6% 0 96.1% 0 98.8% 0 95.4% 0 97.4% 0 98.4% 0 97.6% 0 96.1% 0 96.2% 0 95.2% 0 96.7% 0 98.1% 0 96.6% 0 95.3% 0 99.0% 0 92.9% 0 96.4% 0 97.3% 0 96.5% 0 95.0% 0 97.2% 0 93.1% 0 95.8% 0 96.5% 0 95.3% 0 93.6% 0 97.5% 0 90.7% 0 94.7% 0 96.1% 0 95.2% 0 93.6% 0 96.2% 0 91.0% 0 94.4% 0 93.6% 0 92.3% 0 90.8% 0 95.3% 0 88.3% 0 92.0% 0 93.6% 0 93.2% 0 91.5% 0 94.2% 0 88.1% 0 92.1% 0 94.3% 0 93.3% 0 90.9% 0 96.5% 0 86.7% 0 92.3% 0 93.7% 0 93.4% 0 91.4% 0 95.0% 0 86.3% 0 92.0% 0 30
Appendix 1 (2/4) N -10 % +10% +20% N -10 % +10% +20% 1 % 1 % 1 % 1 % 5 % 5 % 5 % 5 % A B C D E Average A B C D E Average A B C D E Average A B C D E Average A B C D E Average A B C D E Average A B C D E Average A B C D E Average Test Group Elekt. Dim. Manufacturer flux 7 8 9 10 11 12 13 14 100 100 1000 lumen † 101.7% 102.1% 0 99.6% 100.0% 0 98.0% 98.2% 0 97.9% 100.7% 0 98.7% 98.0% 0 99.2% 99.8% 0 99.8% 100.3% 0 99.2% 99.6% 0 97.9% 94.4% 97.7% 1 98.0% 0 98.5% 98.0% 97.8% 0 98.8% 1 101.4% 101.5% 0 99.1% 99.5% 0 99.1% 97.3% 99.6% 0 98.7% 0 98.5% 99.1% 98.0% 0 99.4% 0 99.6% 101.3% 0 99.0% 100.1% 0 97.9% 92.4% 98.7% 0 95.5% 0 98.7% 97.5% 99.5% 0 99.0% 0 101.8% 103.2% 0 99.0% 100.0% 0 98.8% 92.9% 99.7% 0 95.6% 0 98.9% 98.3% 99.4% 0 99.6% 0 102.2% 101.2% 0 99.3% 98.9% 0 98.1% 95.9% 97.7% 0 95.1% 0 98.9% 98.9% 98.5% 0 98.3% 0 100.2% 100.7% 0 99.0% 98.9% 0 97.7% 94.3% 97.8% 0 95.9% 0 100.2% 98.3% 99.0% 0 98.5% 0 100.8% 101.3% 0 99.2% 99.9% 0 98.0% 92.6% 97.8% 0 94.3% 0 98.6% 97.8% 98.5% 0 98.4% 0 Burning hours 2000 lumen † 102.0% 0 4000 lumen † 99.2% 0 100.1% 0 98.1% 0 97.4% 0 95.8% 0 100.5% 0 96.9% 0 99.5% 0 99.1% 0 97.4% 0 97.8% 0 8000 lumen † 97.9% 0 96.0% 0 94.7% 0 97.3% 0 95.8% 0 96.4% 0 12000 lumen † 98.3% 0 97.1% 0 95.3% 0 98.0% 0 96.1% 0 96.9% 0 98.4% 1 97.6% 1 96.3% 1 96.7% 1 98.0% 2 3 3 3 96.9% 2 97.9% 1 96.0% 2 97.5% 2 94.8% 2 95.1% 2 96.6% 2 3 95.9% 0 97.3% 6 96.4% 0 96.8% 8 94.8% 0 95.5% 8 95.6% 0 95.9% 9 101.2% 0 99.2% 0 99.5% 0 99.4% 0 96.9% 0 99.2% 0 101.0% 0 99.7% 0 98.4% 0 95.4% 0 98.0% 0 98.5% 0 100.3% 0 97.9% 0 98.2% 0 98.7% 0 97.3% 0 98.5% 0 98.1% 0 97.5% 0 96.3% 0 93.5% 0 98.3% 0 96.7% 0 98.5% 0 96.4% 0 96.6% 0 96.8% 0 94.3% 0 96.5% 0 96.7% 0 95.9% 0 94.0% 0 91.5% 0 96.8% 0 95.0% 0 98.2% 0 96.3% 1 96.6% 0 97.3% 0 96.4% 0 97.0% 1 97.1% 0 96.0% 0 94.8% 0 92.7% 0 96.7% 0 95.4% 0 102.2% 0 99.0% 0 99.1% 0 95.2% 0 97.0% 0 98.5% 0 99.3% 0 96.5% 0 96.8% 0 93.4% 0 96.3% 0 96.5% 0 97.5% 0 94.5% 0 95.0% 0 91.2% 0 95.1% 0 94.7% 0 97.8% 1 94.8% 0 95.5% 0 92.2% 0 94.4% 0 94.7% 1 100.6% 1 100.0% 1 97.5% 1 97.4% 1 96.2% 1 3 3 3 97.4% 0 94.9% 0 95.7% 0 94.0% 0 94.1% 0 3 90.8% 0 92.0% 0 96.6% 0 96.9% 2 95.8% 0 96.0% 4 94.7% 0 94.0% 4 94.0% 0 94.1% 7 99.9% 0 98.0% 0 97.0% 0 95.8% 0 97.6% 0 97.6% 0 99.7% 0 97.6% 0 96.5% 0 93.4% 0 94.4% 0 96.3% 0 99.2% 0 97.2% 0 97.0% 0 95.0% 0 97.1% 0 97.1% 0 98.8% 0 96.4% 0 95.2% 0 92.6% 0 95.1% 0 95.6% 0 96.4% 0 94.4% 0 94.3% 0 92.4% 0 94.9% 0 94.5% 0 95.6% 1 94.1% 0 93.6% 0 91.2% 1 95.3% 0 94.0% 2 96.6% 0 94.3% 0 96.2% 1 93.5% 0 92.2% 2 3 89.0% 0 89.4% 0 94.5% 0 93.5% 2 94.5% 0 93.1% 4 31
Appendix 1 (3/4) Test Group Elekt. Dim. Manufacturer flux 15 16 17 18 N 15 % -10 % 15 % +10% 15 % +20% 15 % A B C D E Average A B C D E Average A B C D E Average A B C D E Average 100 100 100.3% 99.1% 97.2% 92.7% 99.0% 97.7% 1000 lumen † 99.9% 0 97.9% 0 96.4% 0 90.5% 0 97.8% 0 96.5% 0 100.7% 99.0% 97.7% 93.5% 98.8% 97.9% 99.0% 0 97.6% 0 96.6% 0 90.5% 1 97.0% 0 96.5% 1 99.8% 100.1% 0 99.1% 98.8% 0 97.9% 93.6% 97.5% 0 92.3% 0 99.2% 97.9% 97.7% 0 97.3% 0 101.6% 100.9% 0 98.7% 97.8% 0 97.9% 93.5% 96.9% 0 93.2% 0 99.6% 98.3% 98.4% 0 97.4% 0 Burning hours 2000 lumen † 98.7% 0 97.1% 0 96.0% 0 90.3% 0 96.2% 0 95.7% 0 4000 lumen † 97.6% 0 95.9% 0 95.0% 0 90.6% 0 94.6% 0 94.8% 0 98.6% 0 96.8% 1 96.5% 0 90.3% 1 95.2% 0 95.8% 2 99.1% 0 97.8% 0 96.9% 0 92.0% 0 96.2% 0 96.4% 0 100.1% 0 96.7% 0 96.5% 0 92.5% 0 96.6% 0 96.5% 0 97.3% 0 3 95.0% 0 90.0% 1 93.8% 0 94.4% 4 99.0% 1 96.3% 0 95.7% 0 91.3% 0 95.1% 0 95.2% 1 99.0% 0 95.5% 0 94.5% 0 90.9% 0 95.5% 0 95.1% 0 8000 lumen † 94.9% 0 93.1% 0 92.3% 0 85.0% 0 93.2% 0 91.7% 0 12000 lumen † 95.7% 1 93.7% 0 93.1% 0 87.2% 0 92.1% 0 92.1% 1 95.3% 2 3 3 3 90.0% 2 3 83.1% 2 92.1% 0 90.8% 9 85.8% 2 91.3% 1 89.4% 12 96.5% 1 94.3% 0 93.4% 0 87.8% 0 93.2% 0 92.8% 1 95.5% 1 93.3% 0 93.6% 0 88.6% 0 92.5% 0 92.5% 1 97.8% 2 92.7% 0 92.0% 1 85.8% 0 93.6% 0 91.5% 3 3 92.2% 0 91.1% 1 86.9% 1 92.9% 2 90.7% 7 32
Appendix 1 (4/4) Test Group Elekt. Dim. Manufacturer flux 19 20 21 22 23 24 N Dyn1 Sylvania Philips Osram GE Auralight Average +20% Dyn1 Sylvania Philips Osram GE Auralight Average N Dyn2 Sylvania Philips Osram GE Auralight Average +20% Dyn2 Sylvania Philips Osram GE Auralight Average N Dyn3 Sylvania Philips Osram GE Auralight Average +20% Dyn3 Sylvania Philips Osram GE Auralight Average 100 100 99.3% 97.5% 97.1% 94.3% 97.0% 97.0% 99.3% 97.3% 97.2% 92.7% 96.0% 96.5% 98.1% 97.6% 97.0% 94.0% 95.7% 96.5% 99.7% 97.5% 97.0% 93.0% 96.4% 96.7% 98.2% 97.3% 96.8% 94.3% 95.9% 96.5% 98.8% 97.2% 97.0% 92.9% 96.1% 96.4% 1000 lumen † 96.0% 0 94.6% 0 94.1% 0 89.0% 0 93.8% 0 93.5% 0 96.7% 0 94.8% 0 94.6% 0 88.0% 0 93.1% 0 93.4% 0 96.6% 0 95.9% 0 95.3% 0 90.0% 0 93.4% 0 94.2% 0 98.2% 0 96.1% 0 94.5% 0 88.8% 0 93.8% 0 94.3% 0 97.5% 0 96.2% 0 95.9% 0 93.1% 0 94.5% 0 95.4% 0 97.8% 0 95.9% 0 95.8% 0 89.5% 0 94.4% 0 94.7% 0 Burning hours 2000 lumen † 97.5% 0 4000 lumen † 96.6% 0 95.6% 0 95.8% 0 94.8% 0 94.9% 0 92.1% 0 95.0% 0 95.2% 0 92.6% 0 93.2% 0 94.4% 0 97.4% 0 95.7% 0 95.3% 0 90.1% 0 94.1% 0 94.5% 0 96.4% 0 95.6% 0 95.5% 0 91.5% 0 93.2% 0 94.4% 0 97.6% 0 95.6% 0 94.5% 0 90.1% 0 93.5% 0 94.3% 0 96.8% 0 95.8% 0 95.5% 0 94.7% 0 94.1% 0 95.4% 0 97.4% 0 95.9% 0 96.0% 0 90.2% 0 94.3% 0 94.7% 0 96.3% 0 95.3% 0 95.3% 0 90.0% 0 92.1% 0 93.8% 0 95.7% 0 94.8% 0 95.1% 0 89.8% 0 92.8% 0 93.6% 0 95.3% 0 94.7% 0 95.1% 0 91.8% 0 92.0% 0 93.8% 0 96.0% 0 94.9% 0 94.3% 0 90.9% 0 92.6% 0 93.8% 0 96.1% 0 95.5% 0 95.3% 0 94.8% 0 92.6% 0 94.9% 0 8000 lumen † 94.5% 0 93.3% 0 94.0% 1 88.4% 0 91.3% 0 92.2% 1 94.3% 0 93.4% 0 94.0% 0 86.5% 0 90.3% 0 91.7% 0 94.5% 0 93.6% 0 94.2% 0 89.6% 0 89.8% 0 92.3% 0 95.3% 0 93.9% 0 93.1% 0 88.7% 0 90.2% 0 92.2% 0 95.3% 0 94.6% 0 94.5% 0 93.4% 0 91.0% 0 93.7% 0 95.6% 0 94.3% 0 94.9% 1 87.5% 0 90.2% 0 92.3% 1 12000 lumen † 93.3% 0 91.6% 0 92.7% 1 87.7% 1 90.2% 0 91.2% 2 92.6% 0 91.8% 0 91.9% 2 86.2% 0 89.6% 0 90.2% 2 92.5% 0 91.7% 0 92.2% 0 86.2% 0 87.9% 0 90.1% 0 92.7% 1 91.6% 0 91.6% 0 85.6% 0 88.7% 0 89.8% 1 93.7% 0 93.4% 0 93.3% 0 93.4% 0 89.7% 0 92.7% 0 94.4% 0 92.9% 0 94.2% 2 88.9% 0 88.7% 0 91.4% 2 33
Appendix 2 (1/1) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ave.
Stdev % Date: Research: Burning hours: Number of the test group: Measurer: Nro 220.0
220.0
220.0
220.1
220.0
220.0
220.0
0.0
0.0% Uv V 220.0
220.0
220.0
220.0
220.0
220.0
220.0
220.0
220.0
438.0
439.8
438.7
438.6
440.3
438.8
435.5
4.4
1.0% I mA 427.1
425.4
431.2
432.4
438.6
435.4
435.3
437.3
435.6
16.9.98 Time: 10:45 IDAS WP 3 12 000 01 ET 44.4
44 44.3
42.5
42.6
42.9
43.9
0.7
1.5% Ptot W 44.4
44.3
44.1
44.7
44.1
44.5
44.2
44 44.2
UL V 108.1
107.4
106.5
107.5
104.4
105.9
104.7
103.4
104.7
106.4
105.1
106.9
99.1
99 99.6
104.6
3.0
2.8% 37.3
36.9
37.2
35.4
35.4
35.7
36.9
0.8
2.1% PL W 37.6
37.5
37.2
37.8
36.9
37.4
37.1
36.3
37.1
Φ lm 3049 3031 3047 2957 2979 2958 2931 2931 2913 3113 3109 3143 2793 2776 2823 2970.2
110.4
3.7% 70 71 71 66 65 66 68 1.9
2.8% η lm/W 69 68 69 66 68 66 66 67 66 9.749
9.78
9.936
8.386
8.33
8.435
9.33
0.5
5.4% Φε W 9.843
9.453
9.377
9.373
9.602
9.335
9.322
9.569
9.451
2934 2935 2932 3002 3006 3018 2974 47.7
1.6% CCT K 3026 3023 3035 3000 2999 2995 2903 2902 2905 Ra 85.8
85.9
85.7
84.8
84.8
84.9
84.1
84.2
84.1
84.9
84.8
84.8
85.7
85.5
85.6
85.0
0.6
0.7% 25.4
25.3
25.2
24.4
24.4
24.3
25.2
0.4
1.6% Tamb ° C 25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
25.4
34
