GB/T 45321-2025Measuring methods for the electrical and photometric parameters of filament light sources for motor vehicles (English PDF)

1 Scope

GB/T 45321-2025 specifies how the electrical and photometric parameters of filament light sources for motor vehicles are measured. Filament lamps are still fitted in enormous numbers to vehicles in and from China, and their type approval turns on numbers, luminous flux, luminous intensity in stated directions, the position and dimensions of the filament relative to the reference plane, the power at the test voltage, which are only comparable if the measurement conditions are fixed to a degree most people underestimate: the ageing of the lamp before measurement, the supply stability, the burning position, the stabilisation time and the temperature all move the result. The standard fixes them and describes the apparatus, the measurement procedures and the calculation and expression of results for each parameter, together with the measurement uncertainty. For a lamp maker, a headlamp manufacturer or a photometric laboratory working to Chinese requirements, this is the method behind the type approval numbers.

This document specifies the measurement principles, instruments and equipment, measurement conditions, measurement steps, data processing, and test reports of the electric and photometric parameters, total flux, and chromaticity coordinates of filament light sources for power-driven vehicles. This document is applicable to filament light sources used for power-driven vehicle road lighting and light signal devices and systems (hereinafter referred to as the "light sources"). Filament light sources used for other road vehicles may take this as a reference.

2 Normative References

The contents of the following documents constitute indispensable clauses of this document through the normative references in the text. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 2900.65 Electrotechnical Terminology - Lighting

GB/T 26178 The Measurement of Luminous Flux

GB/T 43081-2023 Lamps and Light Sources for Road Vehicles - Dimensional, Electrical and Luminous Requirements JJG 247-2008 Standard Incandescent Lamp for Total Luminous Flux

3 Terms and Definitions

The terms and definitions defined in GB/T 2900.65 and GB/T 26178, and the following are applicable to this document.

3.1 filament light sources A type of light sources, in which, the only element that generates and emits light when powered is one or multiple filaments.

3.2 test voltage

b) The grade index is not lower than 0.01% and the rated power is not lower than 1 W.

5 Instruments and Equipment...

6 Measurement Conditions

6.1 Working Environment The measurement of light sources shall be carried out in an environment with a temperature of 23 C 5 C and a humidity of less than 80%. Temperature control equipment (such as. air conditioners, heaters, etc.) shall not be placed in a location that allows airflow and radiant heat to be directly transmitted to the thermometer or photometer.

6.2 Ageing Before measurement, use the test voltage to continuously ignite for 1 h to age the light source. For dual-filament light sources, each filament shall be respectively aged. For light sources for which multiple test voltages are specified, the highest test voltage value shall be used. During ageing, the light source reference axis and the filament are in a horizontal state. For a dual-filament light source equipped with a light distribution screen, the light distribution screen shall be located below the low-beam filament. If the light source has an axial filament, the longer filament support shall be located above the filament.

6.3 Ignition Location and Direction When measuring the total flux, the light source shall be located at the center of the integrating sphere, and its direction is.

a) The reference axis and the filament are in a horizontal state, and the filament axis is parallel to the screen;

b) For light sources with transverse filaments (the filament axis is perpendicular to the reference axis), the top of the glass bulb faces the screen;

c) For light sources with axial filaments (the filament axis is parallel to the reference axis), the longer filament support shall be located above the filament;

d) For light sources with a light distribution screen and emitting asymmetric light, the light distribution screen shall be located below the low-beam filament and the side of the light distribution screen edge with an inclined angle faces the screen. Examples of the ignition directions of different types of light sources within the sphere are provided in Appendix A.

6.4 Stabilization Stabilization means that the parameters of the light source do not significantly change within a certain period of time. During stabilization and measurement, the operating environment of the light source shall be the same. Before each measurement, the halogen light source shall be ignited at the test voltage for 4 minutes ~ 5 minutes, and other light sources shall be ignited at the test voltage for 2 minutes ~ 3 minutes, all light sources shall be ignited for 10 min when measuring the chromaticity coordinates. During the last minute of the ignition of the light source, the light output is measured every 20 seconds. When the deviation between the maximum and minimum values of the three readings is within 0.25%, stabilization is achieved. If the requirement is still not met after 15 minutes, the test can be started and the observed fluctuations shall be recorded.

6.5 Voltage and Current When measuring voltage, the voltmeter wiring should be drawn from both ends of the lamp holder near the filament position of the light source to monitor the voltage at the lamp end of the light source under test. When measuring current with power on, a component with a relatively small contact resistance shall be used to clamp the lamp holder of the light source, for example, a special lamp holder for measurement, to reduce the contact resistance and measurement errors. Typical examples of light source power-on and lamp holder voltage monitoring are shown in Appendix B. Voltage and current tests use the four-wire line power supply.

7 Measurement Steps and Data Processing

7.1 Pre-heating of Measurement Equipment Before measuring electric and photometric parameters, the equipment shall be turned on for pre-heating, so as to stabilize its performance. If the total flux is to be measured, a light source with a power similar to that of the light source under test shall be ignited in the integrating sphere for not less than 30 minutes, the sphere wall shall be baked to de-humidify, and the detector shall be pre-illuminated.

7.2 Measurement of Electric Parameters The measurement steps are as follows:

a) After the light source under test has been aged in accordance with the requirements of 6.2, install it to the center of the sphere in the mode of

6.3 and in accordance with the provisions of 6.5, connect it to the measurement system shown in Figure 1 or Figure

2.Adjust the power output, so that the reading of the V2 meter is the test voltage. After the light source reaches the stabilization described in 6.4, respectively read the displayed values u and U of the V1 and V2 voltmeters in Figure 1 or read the voltmeter reading U and the ammeter reading I in Figure

2.The voltage adjustment process shall

d) In accordance with Formula (7), calculate the total flux of the light source under test. Where, Phin

---the total flux of the light source under test; Phit

---the total flux of the standard lamp; pn(lambda)

---the relative spectral power distribution of the light source under test; Pt(lambda)

---the relative spectral power distribution of the standard lamp; V(lambda)

---the spectral luminous efficiency function of the CIE photopic standard photometric observer; lambda

---the wavelength test interval of the (relative) spectral power distribution of the light source.

7.3.3 Total flux absorption correction factor When the overall dimensions of the standard lamp and the light source under test greatly differ or the glass bulb form and lamp holder shape are obviously different, an auxiliary light source shall be used to measure the absorption correction factor k of each type of light source under test. The method shall comply with the provisions of Appendix C. After the absorption correction, the total flux Phi of the light source under test is calculated in accordance with Formula (8).