Renewable Energy

LLE smd LED 6000K 150cm single, no luminaire

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

presents a measurement set of one 1500 mm smd-LED tube without luminaire. 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 6766 K Bright white
Luminous intensity Iv 480 Cd
Beam angle 130 deg A wide beam, which is to be expected from an FL-tube.
Power P 22.9 W
Power Factor 0.48 For every 1 kWh net power consumed, there has been 1.8 kVAhr for reactive power.
Luminous flux 1681 lm
Luminous efficacy 73 lm/W
CRI_Ra 77 Color Rendering Index.
Coordinates chromaticity diagram x=0.3105 and y=0.3138
Fitting FL-tube
L x W x H external dimensions 1500 x 26 x 26 mm External dimensions of the tube in a simple luminaire that only holds the tube (no cover, no reflector).
L x W dimensions luminous area 1460 x 21 mm Dimensions of the luminous area (used in Eulumdat file). This is the area of the led strips in he tube.
General remarks The ambient temperature during the whole set of measurements was 19.5 deg C.

Warm up effect: the illuminance as well as the power consumed decrease a little. It is a small and negligible effect.

Voltage dependency: consumed power and illuminance are dependent from the light bulb voltage. It is a linear dependence.

For the eulumdat file follow this link.

The light tube

The led tubes use smd LEDs. At the back side of the tube the ribs of the aluminum heatsink are visible. These tubes are robust and heavy tubes.

At the top the front view, then side view and at bottom the back view.

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 tube itself has a platic transparent cover with ribs in it, explaining the somewhat dented curvature of the radiation pattern in this plane.

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

Illuminance at 1 m distance, aka 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 130 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 1681 lm.

Luminous efficacy

The luminous flux being 1681 lm, and the power of the lightbulb being 22.9 W, yields a luminous efficacy of 73 lm/W.

A power factor of 0.48 means that for every 1 kWh net power consumed, a reactive component of 1.8 kVAr was needed.

Light bulb voltage 230 V
Light bulb current 209 mA
Power P 22.9 W
Apparent power S 48.1 VA
Power factor 0.48

Color temperature and Spectral power distribution

The spectral power distribution of this light bulb.

The measured color temperature is about 6750 K, bright white.

Chromaticity diagram

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

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

Its coordinates are x=0.3105 and y=0.3138.

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 77 is lower than 80 which is considered a minimum value for indoor usage.

Note: the chromaticity difference is 0.007 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], color temperature CT or correlated color temperature CCT [K], the lamppower 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 depend on the light bulb voltage applied. This dependence is linear.

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 – 2 % and will not be visible or noticeable.

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].

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

No noticeable effects seen. The illuminance and power consumption decrease < 10 % during the warm up period that takes 30 minutes. This effect is small and hence there is no meaningful warm up period.

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