Relationship Between Total Flux, Nominal Flux and Test Flux

A lamp is composed of one or more luminous light sources with a shell (namely lamps, for example, some down lamp can be installed in one tube or two tubes). The light source and lamps can be separated.

Nominal flux of each light source: it refers to the Nominal luminous flux of each light source installed in the Test lamps. It is expressed as φNominal

Test flux of each light source: it refers to the Test luminous flux of the light source installed in the Test lamps when testing the luminosity distribution of lamps. It is expressed as φTest

The number of light source: it refers to the number of the light source installed within the lamps. It is expressed as N

Total flux: it refers to the total luminous flux output after the installation of the light source with the Nominal flux in the lamp. It is expressed as φTotal

Luminary’s efficiency: it refers to the ratio of the luminous flux emitted from the light source within the lamp and the total luminous flux outputted from the lamp. It is expressed as η.

Before the test, the Nominal flux of each light source and the Test flux of each light source should be set to be the same values, namely the Test flux of each light source. The total flux Test is the total flux outputted from the current light source of the lamps. It is expressed as φOriginal.

After the test is completed, the total flux can be revised according to different Nominal flux of each light source, the relations are as follows:

φTotal = (φNominal * N) / (φTest * N) * φOriginal

For most of the LED lamps, because light source and the shell is an indivisible whole, there would be not necessary to point out the light source and the shell, neither the lamps efficiency. Generally the Nominal flux of each light source and the Test flux of each light source are recommended to be set to the same value. Before the test, a value can be input in advance, and then the value of the total flux is input after the completion of the test.

Application:

1. Traditional lamps and lanterns: one lamp use a light source for the test, after that, when replacing the same type of light source (same shape, but not the same power or the flux only), the total flux of the lamp can be got by modifying the Nominal flux of each light source without retesting.

2.Lamps and lanterns with integrated packaging LED light source: in the same situation for two times of light distribution (namely lens and reflecting cover shell, etc) , the total flux of the whole lamp can be got only by revising the Nominal flux of each light source as the luminous flux of the integrated packaging LED light source.

3. Scattered LED lamps and lanterns: if there is more than one 1 W LED lamps, the Nominal flux of each light source can also be set as the flux of a single 1 W LED, and the light source number can be input as the actual use of LED quantity. Special attention should be paid because the existence of many differences between the single LED and many LEDs may cause the luminous flux error.