LLE smd LED 3000K 60cm single no luminaire

Posted by Marcel van der Steen in Led lights, Light measurements No Comments»

presents a measurement set of one 600 mm smd-LED tube alone, without any luminaire. The only luminaire used was one simple one that only holds the tube. In this article the measurement data can be found as well as in Eulumdat format.
See this overview for a comparison with other light bulbs.

Summary measurement data

parameter meas. result remark
Color temperature 3380 K Bright white
Luminous intensity Iv 138 Cd
Beam angle 139 deg A wide beam, which is to be expected from an FL-tube.
Power P 8.5 W
Power Factor 0.39 For every 1 kWh net power consumed, there has been 2.3 kVAhr for reactive power.
Luminous flux 469 lm
Luminous efficacy 55 lm/W
CRI_Ra 66 Color Rendering Index.
Coordinates chromaticity diagram x=0.4317 and y=0.4393
Fitting FL-tube
L x D external dimensions 600 x 26 mm External dimensions of the tube
L x W dimensions luminous area 550 x 21 mm Dimensions of the luminous area (used in Eulumdat file). This is here the area of the platic part on which the leds are mounted.
General remarks The ambient temperature during the whole set of measurements was 22.5-23.5 deg C.

Warm up effect: marginal effect.

Voltage dependency: marginal changes due to a change in light bulb voltage.

For the eulumdat file follow this link.

Eulumdat lichtdiagram

With this article an eulumdat file is added. This is a file that a.o. indicates the radiation pattern around the light bulb. There are more parameters in the file, and these all can be read with help of the free open source program Qlumedit.

An interesting graph is the light diagram, indicating the intensity in the C0-C180 and the C90-C270 plane.

The light diagram giving the radiation pattern in the C0-C180 and C90-C270 planes.
The C0-C180 plane is perpendicular to the length axis of the tube. It indicates the luminous intensity sideways of the tube.

The C90-C270 plane indicates the radiation pattern in the plane in the same direction as the tube’s length.

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.

The radiation pattern of the light bulb.

This radiation pattern shows a wide beam.

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

The intensity measurements (of each turn angle) as function of inclination angle.

This plot shows per inclination angle the intensity measurement results for each turn angle at that inclination angle.

When using the average values per inclination angle, the beam angle can be computed, being 139 degrees. However, this value is dependent from the plane observed.

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 lamp is a luminous flux of 469 lm.

Luminous efficacy

The luminous flux being 469 lm, and the power of the light bulb being 8.5 W, yields a luminous efficacy of 55 lm/W.

A power factor of 0.39 means that for every 1 kWh net power consumed, a reactive component of 2.3 kVAr was needed.

Light bulb voltage 230 V
Light bulb current 94 mA
Power P 8.5 W
Apparent power S 21.6 VA
Power factor 0.39

Color temperature and Spectral power distribution

The spectral power distribution of this light bulb.

The measured color temperature is about 3400K, being close to warm white.
This measurement is done straight underneath the light bulb. This color temperature can also be measured when looking at the light bulb under different inclination angles.

The color temperature dependent from the inclination angle.

The dependency is different for different turn-angles. Generally there is a decrease of the color temperature, of about 10 %.

Chromaticity diagram

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

The light coming from this light bulb is at a distance from the Planckian Locus (the black path in the graph).

Its coordinates are x=0.4317 and y=0.4393.

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).

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.

CRI of the light of this lightbulb.

The value of 66 is lower than the 80 which is considered a minimum value for indoor usage.

Note: the chromaticity difference is 0.015 indicates the distance to the Planckian Locus. Its value is higher  than 0.0054, which means that the calculated CRI result is not meaningful.

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 lamp parameters measured: illuminance E_v [lx], correlated color temperature CCT [K], the lamp power P [W] and the luminous efficacy [lm/W].

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

The power consumed and the illuminance measurements do depend very little on the light bulb voltage applied.

To check whether this dependency can lead to visible changes in illuminance for possible grid voltage changes, it is noted what variations occur when the lamp voltage varies around 230 V + and – 5 V. Then the illuminance varies between + and – 0.2 %. It will not be visible.

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], correlated color temperature CCT [K], the lamp power P [W] and the luminous efficacy [lm/W].

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

No noticeable effects seen. The illumination changes less than 4 % over the warm-up time of 40 minutes. This is so little that a definition of the warm-up time is not relevant.

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