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Loko Led Tube light 150 cm

Posted by Marcel van der Steen in Led lights, Light measurements Add comments

loko_ledtl presents an 150 cm long led tube light. The tube has smd leds and emits a neutral white light. Also exist the 60 cm version (warm white) and 120 cm version (cold white).

This article shows the measurement results. Many parameters are also found in the Eulumdat file.

See this overview for a comparison with other light bulbs.

Summary measurement data

parameter meas. result remark
Color temperature 4461 K Neutral white
Luminous intensity Iv 723 Cd Measured straight underneath the lamp
Beam angle 110 deg 110º for the C0-C180 plane (crosses the length direction of the tube), and 107º for C90-C270 plane (along the length direction of tube).
Power P 24.1 W Follow the link for more electrical and temperature properties.
Power Factor 0.92 For every 1 kWh net power consumed, there has been 0.4 kVAhr for reactive power.
Luminous flux 2028 Lm
Luminous efficacy 84 Lm/W
CRI_Ra 70 Color Rendering Index.
Coordinates chromaticity diagram x=0.3645 and y=0.3760
Fitting FL-tube This tube is connected directly to the 230 V grid.
PAR-value 5.9 μMol/s/m2 The number of photons seen by an average plant when it is lit by the light of this light bulb. Value valid at 1 m distance from light bulb.
PAR-photon efficacy 0.7 μMol/s/We The toal emitted number of photons by this light, divided by its consumption in W. It indicates a kind of efficacy in generating photons.
S/P ratio 1.6 This factor indicates the amount of times more efficient the light of this light bulb is perceived under scotopic circumstances (ow environmental light level).
D x L external dimensions 29 x 1496 mm External dimensions of the lamp (D = diameter, L = Length without pins).
L x W luminous area 1474 x 24 mm Dimensions of the luminous area (used in Eulumdat file). This is equal to the surface of area on which the leds are mounted.
General remarks The ambient temperature during the whole set of measurements was 22-24.5 deg C. The maximum temperature of the tube light gets about 21 degrees hotter than ambient.
Warm up effect: during the warm up time the illuminance decreases with 9 % and the consumed power with 3 %.

Voltage dependency: the power consumption and illuminance do not significantly depend on the voltage when it is varied from 200 – 250 V.

Measurement report (PDF) olino-pdf
Eulumdat file olino_eulumdat Right click on icon and save the file.

Overview table

loko_ledt_150cm_summary2

The overview table is explained on the OliNo website. Please note that this overview table makes use of calculations, use this data with care as explained on the OliNo site. E (lux) values are not accurate, when within 5 x 1474 mm ≈ 7400 mm. Within this distance from the lamp, the measured lux values willl be less than the computed values in this overview as the measurements are then within the near field of the lamp.

Eulumdat light diagram

This light diagram below comes from the program Qlumedit, that extracts these diagrams from an Eulumdat file. It is explained on the OliNo site.

loko_ledt_150cm_light_diagram

The light diagram giving the radiation pattern.

It indicates the luminous intensity around the light bulb. The direction C90-C270 has a beam comparable to that of the C0-C180 plane.

Illuminance Ev at 1 m distance, or luminous intensity Iv

Herewith the plot of the averaged luminous intensity Iv as a function of the inclination angle with the light bulb.

loko_ledt_150cm_pp_avg

The radiation pattern of the light bulb.

This radiation pattern is the average of the light output of the light diagram given earlier. Also, in this graph the luminous intensity is given in Cd.

These averaged values are used (later) to compute the lumen output.

loko_ledt_150cm_ev_dep_kantelhoek

Intensity data of every measured turn angle at each inclination angle.

This plot shows per inclination angle the intensity measurement results for each turn angle at that inclination angle. There normally are differences in illuminance values for different turn angles. However for further calculations the averaged values will be used.

When using the average values per inclination angle, the beam angle can be computed, being 110º for the C0-C180 plane (crossing the length direction) and 117º in the C90-C270 plane (along the length direction).

Luminous flux

With the averaged illuminance data at 1 m distance, taken from the graph showing the averaged radiation pattern, it is possible to compute the luminous flux.

The result of this computation for this light spot is a luminous flux of 2028 Lm.

Luminous efficacy

The luminous flux being 2028 Lm, and the power of the light bulb being 24.1 W, yields a luminous efficacy of 84 Lm/W.

Electrical properties

A power factor of 0.92 means that for every 1 kWh net power consumed, a reactive component of 0.4 kVAr was needed.

Lamp voltage 230 VAC
Lamp current 114 mA
Power P 24.1 W
Apparent power S 26.2 VA
Power factor 0.92

Of this light bulb the voltage across ad the resulting current through it are measured and graphed. See the OliNo site how this is obtained.

loko_ledt_150cm_u_i_waveforms

Voltage across and current through the lightbulb

This waveforms have been checked on requirements posed by the norm IEC 61000-3-2:2006 (including up to A2:2009). See also the explanation on the OliNo website.

loko_ledt_150cm_harmonics

Harmonics in in the current waveform and checked against IEC61000-3-2:2006

There are no limits for the harmonics for led lighting equipment <= 25 W.

The Total Harmonic Distortion of the current is computed as 20 %.

Temperature measurements lamp

ir_0312

Overview, look for the hotspots

ir_0313ir_0314

The warmest position on the metal heat sink, measured on a piece of masking tape

status lamp > 2 hours on
ambient temperature 24 deg C
reflected background temperature 24 deg C
camera Flir BCAM
emissivity 0.95(1)
measurement distance 0.10 m (closest zoom)
IFOVgeometric 0.4 mm
NETD (thermal sensitivity) 100 mK

(1) The emissivity of the masking tape is used which is about 0.95. The masking tape is so thin that it quickly takes the same temperature as the light bulb’s heat sink.

The tube on its hotttest side gets a bit hotter than warm-to-the-touch, being 45 deg C.

Color temperature and Spectral power distribution

loko_ledt_150cm_powerspectrum_at_1m_distance

The spectral power distribution of this light bulb, energies on y-axis valid at 1 m distance.

The measured color temperature is about 4450 K which is neutral white.

This color temperature is measured straight underneath the light bulb. Below a graph showing the color temperature for different inclination angles.

loko_ledt_150cm_cct_function_of_incl

Color temperature as a function of inclination angle.

The measurement of CCT is measured for inclination angles up to 75º since then the illuminance value was decreased to very low values (< 5 lux).

The beam angle for the C0-C180 is 110º, meaning a 55º inclination angle. In this area the majority of the light is present. The variation in correlated color temperature in this area is ≈ 4 %.

PAR value and PAR spectrum

To make a statement how well the light of this light bulb is for growing plants, the PAR-area needs to be determined. See the OliNo website how this all is determined and the explanation of the graph.

loko_ledt_150cm_par_spectra_at_1m_distance

The photon spectrum, then the sensitivity curve and as result the final PAR spectrum of the light of this light bulb

parameter value unit
PAR-number 5.9 μMol/s/m²
PAR-photon current 16.5 μMol/s
PAR-photon efficacy 0.7 μMol/s/W

The PAR efficiency is 63 % (valid for the PAR wave length range of 400 – 700 nm). So maximally 63 % of the total of photons in the light is effectively used by the average plant (since the plant might not take 100 % of the photons at the frequency where its relative sensitivity is 100 %).

S/P ratio

The S/P ratio and measurement is explained on the OliNo website. Here the results are given.

loko_ledt_150cm_s_and_p_spectra_at_1m_distance
The power spectrum, sensitivity curves and resulting scotopic and photopic spectra (spectra energy content defined at 1 m distance).

The S/P ratio is 1.6.

More info on S/P ratio can be found on the OliNo website.

Chromaticity diagram

loko_ledt_150cm_chromaticity

The chromaticity space and the position of the lamp’s color coordinates in it.

The light coming from this lamp is close at the Planckian Locus (the black path in the graph).

Its coordinates are x=0.2645 and y=0.3760.

Color Rendering Index (CRI) or also Ra

Herewith the image showing the CRI as well as how well different colors are represented (rendered). The higher the number, the better the resemblance with the color when a black body radiator would have been used (the sun, or an incandescent lamp). Practical information and also some critics about the CRI can be found on the OliNo website.

Each color has an index Rx, and the first 8 indexes (R1 .. R8) are averaged to compute the Ra which is equivalent to the CRI.

loko_ledt_150cm_cri

CRI of the light of this lightbulb.

The value of 70 is lower than 80 which is considered a minimum value for indoor usage.

Note: the chromaticity difference is 0.0047 indicates the distance to the Planckian Locus. There is no norm yet that states what the max deviation from white light is allowed to be.

Voltage dependency

The dependency of a number of lamp parameters on the lamp voltage is determined. For this, the lamp voltage has been varied and its effect on the following light bulb parameters measured: illuminance E_v [lx], the lamppower P [W], the (Correlated) Color Temperature [K] and the luminous efficacy [Lm/W].

loko_ledt_150cm_voltagedependency

Lamp voltage dependencies of certain light bulb parameters, where the value at 230 V is taken as 100 %.

The illuminance and consumed power do not (significantly) vary when the voltage is varied, in a linear matter.

When the voltage at 230 V varies with + and – 5 V, then the illuminance varies < 0.1 %, so when abrupt voltage changes occur this effect is not visible in the illuminance output.

Warm up effects

After switch on of a cold lamp, the effect of heating up of the lamp is measured on illuminance E_v [lx], color temperature CT or correlated color temperature CCT [K], the lamppower P [W] and the luminous efficacy [lm/W].

loko_ledt_150cm_startupeffect

loko_ledt_150cm_startupeffect_end

Effect of warming up on different light bulb parameters. At top the 100 % level is put at begin, and at bottom at the end.

The warm up time is about 30 minutes. During that time the illuminance decreases 9 % and the consumed power with 3 %.

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