Instruction manual
21
2.14.1 Advantages for Users
The following advantages for users arise from cut-off technology:
6-10 % higher luminaire efficiency
highest lamp life
2-3 W lower losses per lamp
reduced load of air condition
2.14.2 Physical Background
T5/∅ 16 mm-fluorescent lamps FH
®
…HE and FQ
®
…HO are designed to
have their maximum lumen output at 35 °C (compared to 25 °C for
T8/∅ 26 mm). For T5/∅ 16 mm-fluorescent lamps the so-called cold spot
(the point where mercury condensates in a discharge tube, stamped end of
the lamp) is located behind the electrode (see graphics) which means near
the source of heat.
The value of the luminous flux at the ambient temperature of 35 °C is only
informative for the luminaire manufacturer. Significant is the value of the
cold spot temperature. This value is measured at the socket of the stamped
side, approx. in a distance of 2 mm of the glass. For an optimized luminous
flux this value should be between 45 °C and 50 °C. This is shown at the so
called ‘Horseshoe curves’ where the luminous flux is shown in relation to
the lamp ambient temperature.
The cold spot of the T5/∅ 16 mm fluorescent lamps is influenced by
permanent filament heating. This means that higher temperatures reduce
the luminous flux. ECG with cut-off technology reduce the losses of the
system and are optimized regarding the maximum luminous flux of the
Rel.
Lum-
inous
flux
Only cut-off technology can fulfill lifetime
Lifetime [hours]
5.000h
10.000h
16.000h
14.000h
20.000h
100%
90%
80%
70%
60%
50%
40%
Conventional
ECG circuitry
Cut-off
13. 16.
16. 20.
Significantly lower temperatures at the
lamp electrodes
New circuitry wihtout permanent filament heating
(cut-off technology)
rel.
Licht-
strom
Umgebungstemperatur (°C)
Cut-off advantage for the luminaire
110
100
90
80
70
60
10 20 30 40 50
35°C
Conventional
ECG circuitry
Cut Offk
6 – 10% higher
luminaire efficiency for
direct lighting
I
Stift
= I
Lampe
I
Lampe
I
Stift
Cold Spot
app. 40°C
12.000h
18.000h
Rel.
Lum-
inous
flux
Only cut-off technology can fulfill lifetime
Lifetime [hours]
5.000h
10.000h
16.000h
14.000h
20.000h
100%
90%
80%
70%
60%
50%
40%
Conventional
ECG circuitry
Cut-off
Conventional
ECG circuitry
Cut-off
13. 16.
16. 20.
Significantly lower temperatures at the
lamp electrodes
New circuitry wihtout permanent filament heating
(cut-off technology)
rel.
Licht-
strom
Umgebungstemperatur (°C)
Cut-off advantage for the luminaire
110
100
90
80
70
60
10 20 30 40 50
35°C
Conventional
ECG circuitry
Cut Offk
6 – 10% higher
luminaire efficiency for
direct lighting
rel.
Licht-
strom
Umgebungstemperatur (°C)
Cut-off advantage for the luminaire
110
100
90
80
70
60
10 20 30 40 50
35°C
Conventional
ECG circuitry
Cut Offk
6 – 10% higher
luminaire efficiency for
direct lighting
I
Stift
= I
Lampe
I
Lampe
I
Stift
Cold Spot
app. 40°C
12.000h
18.000h
Cold Spot T
Hg opt.
≈ 40°C
T8 (Ø 26 mm)
T12 (Ø 38 mm)
T5 (Ø 16 mm)
Cold Spot T
Hg opt.
≈ 40°C
T8 (Ø 26 mm)
T12 (Ø 38 mm)
T5 (Ø 16 mm)