Investigation of efficiency and quality of functioning of led lighting elements of electrical systems at the maximum permissible ambient temperature

Based on the results of the study of the elements of the electrical system, the operability and quality of their functioning are determined by the example of the use of LED filament lamps for lighting during their continuous operation at the maximum permissible ambient temperature equal to 50 °С.THE PURPOSE. The relevance of this work is determined by the lack of information about the operability and quality of functioning of filament LED lamps during their continuous operation in conditions of elevated ambient temperature, taking place in boiler-turbine shops of thermal power plants, foundries of factories, bakeries of bakeries, in the tunnels of coal mines and divisions of other enterprises. It is established that the working life of the Gauss LED filament lamps with a power of 10 W, containing 4 filaments, is 70-75 days, and with 8 filaments only 22-24 days. Degradation of filament lamps with 8 filaments at the maximum permissible ambient temperature of 50 °С. occurs at a rate of 0.45-0.50 % per day. It is shown that a filament LED lamp with 4 filaments, if it is operated for 4.5 hours a day in conditions of elevated ambient temperature, can work for almost more than one year. METHODS. The resource of filament and typical LED lamps of different power is considered in comparative terms when they are operated at a relatively high ambient temperature.RESULTS. It is established that a 10 W filament LED lamp with 4 filaments has an energy resource, as well as a high-quality standard LED lamp. At the same time, the temperature of its body is no more than 40 °С, which is almost 2 times less. By increasing the distance between the filaments due to the use of a smaller number of filaments, it is possible to increase the power supply by 2 times and the corresponding luminous flux by 1.5 times. CONCLUSION. In preliminary experiments with a filament lamp of the new design of the Diall model, it was found that the use of longer filaments (45 mm) in it, instead of the previously used ones (30 mm), allows to increase the quality of their functioning by about 4 times when they are operated under the same ambient temperature conditions.

Research Of Long-Term Lighting Tests Of Led retrofit And Filament Lamps

The paper analyzes the results of comparative studies of the light and engineering characteristics of LED retrofit lamps and filament lamps of the A60 form factor of nine manufacturers: Uniel (Russia – China), JazzWay (Russia – China), Philips (the Netherlands), Ecola (China), Wolta (Germany), Feron (Russia), Rev (Germany), Osram (Germany), Forza (China) – luminous flux, power consumption, correlated colour temperature, luminous efficacy, flicker index, spectral distribution of the radiation flux density during 6000 hours of lamps burning. The test results show that: а) the measured value of the initial luminous flux of all LED retrofit lamps corresponds to the declared; б) the measured value of the initial luminous flux of filament LED lamps is lower than the declared values by an average of 19 %; в) high value of the luminous flux maintenance factor after 6000 hours of burning among LED retrofit lamps showed Uniel LED10 W 4000 К (94.5 %), Philips Essential LED9 W 6500 K (96.2 %), Wolta LX 12 W 3000 К (95.3 %), for JazzWay PLED-SP 10 W 5000 K and Ecola Classic LED10.2 W 4000 K lamps, the luminous flux maintenance factor was less than 90 %; г) the luminous flux maintenance factor after 6000 hours of burning of all filament LED lamps ranged from 91.3 % to 96.4 %, except for the Feron LB‑57 7 W 2700 K lamp – 89.3 %. According to the test results, only for the Uniel LED10 W 4000 K lamp, the measured values of the light and engineering characteristics and the flicker index, including after 6000 hours of burning, correspond to the declared ones. The high luminous flux maintenance factor after 6000 hours of burning allows this lamp to be classified as A-category in terms of decreasing luminous flux.

The evolution of headlight devices in the work of otorhinolaryngologists

Invention and improving the methods of ENT examination are closely connected with the technological inventions of the 19th and 20th centuries. The invention of the classical exam head mirror in 1861 and improvement of the manufacturing of compact and powerful sources of light (filament lamps) at the time caused the researchers to create new devices for ENT examination. In particular, a head-mounted electro-mirror was created, the principle of which later became the basis for the development of fiber-optic headlamps. The emergence of powerful halogen and xenon light sources in the mid-20th century and the use of fiber-optics technology led to the development of fundamentally new mirror less headlamps. The traditional head-mounted reflector has gradually disappeared from the practice of an otolaryngologist. For our part, we can see how fiber-optic headlamps have been progressively replaced by heavy-duty LED headlamps over the last nine years. In order to determine the effectiveness of each available headlamp type and to answer the question of whether there is a benefit in using and maintaining a reflector headlamp, and to determine which current head-lamps are effective, we conducted our own research. Summing up the results, we came to the conclusion that despite its historic role in the development of otorhinolaryngology, the headlamp reflector through its low, in comparison with modern illuminators, characteristics have lost its relevance and, apparently, nowadays can serve as a museum exhibit. The head-mounted LED illuminator, a 21st century device, is gaining in popularity and is gradually becoming the standard for use in primary ENT diagnosis and during otorhinolaryngological surgical interventions. Its features such as full autonomy, lightweight, ease of use – especially the alignment of the light beam with the surgeon's eye – long operating time without recharging the battery (7 to 30 days) – depending on the manufacturer and the workload of the device – is beyond competition with any other head-mounted device for ENT organ examination.

Comparative Analysis Of The Characteristics Of Led Filament Lamps For Household Lighting

This paper examines the characteristics of LED filament lamps from various manufacturers: LLC “ Lisma “(Russia), an American company with production in China “ GENERAL LIGHTING CO.LTD”, a joint Chinese-Russian company “ Uniel “and Taiwan company” Smartbuy “ in the A60 bulb – the time of stabilization of characteristics, luminous flux, colour temperature, colour rendering index, flicker index, radiation spectrum during 6000 hours of burning. The research was carried out on the Gooch&Housego measuring system. The results of experimental studies that showed that the clear leader in the test results is the lamp SDF‑8 (LISMA), according to GOST of all tested samples of led filament lamps, it can be recommended for lighting in lighting devices for household lighting.

Results from Verification of Reference Irradiance and Radiance Sources Laboratory Calibration Experiment Campaign

We present the results from Verification of Reference Irradiance and Radiance Sources Laboratory Calibration Experiment Campaign. Ten international laboratories took part in the measurements. The spectral irradiance comparison included the measurements of the 1000 W tungsten halogen filament lamps in the spectral range of 350 nm–900 nm in the pilot laboratory. The radiance comparison took a form of round robin where each participant in turn received two transfer radiometers and did the radiance calibration in their own laboratory. The transfer radiometers have seven spectral bands covering the wavelength range from 400 nm–700 nm. The irradiance comparison results showed an agreement between all lamps within ±1.5%. The radiance comparison results presented higher than expected discrepancies at the level of ±4%. Additional investigation to determine the causes for these discrepancies identified them as a combination of the size-of-source effect and instrument effective field of view that affected some of the results.

Thermal Analysis and Optimization of Light-Emitting Diodes Filament Lamp

Due to the high efficiency, light-emitting diodes (LED) filament lamps have become more and more popular alternative to the incandescent lamp. However, the heat generated by the LED chips is traditionally dissipated by relying on the natural convection within lamps, resulting in poor heat dissipation performance for LED filament lamps. A numerical simulation model of the typical LED filament lamp was established to simulate and analyze the heat dissipation and airflow phenomenon of LED filament lamps in this study. In addition, increasing lamp sizes, increasing phosphor diameters, and using finned phosphor layers were considered as optimization measures to improve the heat dissipation performance of LED filament lamps. When these optimization measures are applied, chip junction temperatures are reduced. A reduction of 6.9 °C is seen when the lamp radius is increased from 25 mm to 31 mm. When the phosphor diameter is increased to 4 mm from 2 mm, the junction temperature is reduced by 17.2 °C. Integration of a finned phosphor layer where there are 12 fins at a height of 1 mm and thickness of 0.2 mm in the layer decreased the junction temperature by 10.9 °C. These optimization results provide technical support for the design and manufacture of LED filament lamps, and thermal analysis results provide theoretical support for the promotion of these optimization methods.

Optimization of Helium Inflating on Heat Dissipation and Luminescence Properties of the A60 LED Filament Lamps

LED filament lamp has the characteristics of nearly 360° lighting angle, high brightness, and low energy consumption, turning it gradually into the best substitute for traditional incandescent lamps. At present, due to the limitations of heat dissipation, the development of high-power LED filament lamp is restricted. Helium is a rare gas with small density and high heat transfer coefficient. It can be used as a cooling and protective gas for LED filament lamp. In this paper, we investigated the effects of helium on the heat dissipation and luminescence performance of the A60 LED filament lamps by detecting the changes of junction temperature, color temperature, and luminous flux of different ratios helium inflating in the different power A60 LED filament lamps. Through the experiment, we found the most cost-effective ratio of helium gas in the A60 LED filament lamps without improving the lamp size and the filament diameter.