Electrical consequences of large-scale replacement of metal halide by LED luminaires

2016 ◽  
Vol 50 (2) ◽  
pp. 282-293 ◽  
Author(s):  
MJ Hermoso-Orzáez ◽  
JI Rojas-Sola ◽  
A Gago-Calderón
Keyword(s):  
Large Scale ◽  
Thermal Protection ◽  
Metal Halide ◽  
Light Sources ◽  
Electrical Parameters ◽  
Large Power ◽  
Start Up ◽  
Before And After ◽  
Inrush Currents ◽  
Metal Halide Lamps

The recent trend for large-scale replacement of luminaires using discharge light sources with LED luminaires without any significant adjustments to the electrical installation has generated controversy. This study examines the main electrical measures in a large outdoor lighting installation before and after the replacement of a large number of metal halide floodlights with LED luminaires. The electrical parameters of both technologies are discussed in detail and compared, with special attention given to the odd-numbered harmonics of voltage and current, the generated wave deformation, currents in the neutral conductor, the wattless reactive volt amps and the peak inrush currents. At cold start-up, the LED luminaires generate large power-on currents, much larger than those generated by the metal halide lamps, despite requiring 36% less real installed power. This is a basic problem to be solved when planning a public lighting renovation with LED luminaires as the rest of electrical parameters are reduced. To address this problem, it is proposed to energise the luminaires using magneto-thermal protection circuits with slow trip curves that will tolerate the large short-term inrush currents.

Metal halide lamps: Gravitational influence on color separation

2006 ◽  
Vol 78 (6) ◽  
pp. 1239-1252 ◽  
Author(s):  
W. W. Stoffels ◽  
A. J. Flikweert ◽  
T. Nimalasuriya ◽  
J. J. A. M. van der Mullen ◽  
G. M. W. Kroesen ◽  
...  
Keyword(s):  
Large Scale ◽  
High Efficiency ◽  
Numerical Models ◽  
Metal Halide ◽  
Light Sources ◽  
Color Separation ◽  
Gravitational Influence ◽  
Metal Halide Lamps ◽  
And Diffusion ◽  
Diffusion Flows

Metal halide lamps are very efficient light sources based on a Hg plasma arc with metal halide salt additions. In spite of their high efficiency, the lamps suffer from several problems, such as color separation and instabilities, which currently hinder large-scale use. These phenomena are caused by a complex interaction of convection and diffusion flows in the plasma. In order to unravel the various contributions, experiments under microgravity have been performed where convection is absent. The experiments confirm the previously held qualitative views, but also provide absolute data on densities and temperatures that will be used to validate numerical models of these lamps.

Accelerating Start-up of Metal Halide Lamps

2006 ◽  
Author(s):  
Jia Chen ◽  
Kong Ng ◽  
Chin Moo ◽  
Sheng Tang ◽  
Ching Lee
Keyword(s):  
Metal Halide ◽  
Start Up ◽  
Metal Halide Lamps

Application of LED in Marine Fishery

2013 ◽  
Vol 765-767 ◽  
pp. 213-216
Author(s):  
Wen Qing Shi ◽  
Zheng Ye Xiong ◽  
Yong Qiang Li ◽  
Cun You Huang
Keyword(s):  
High Energy ◽  
Economic Benefits ◽  
Metal Halide ◽  
Light Sources ◽  
Market Demand ◽  
Led Light ◽  
Marine Fishery ◽  
Incandescent Lamps ◽  
Metal Halide Lamps ◽  
Chinese Marine

Aiming at the high energy-consuming characteristics of Chinese marine fishery, the application of LED in Chinese marine fishery is analyzed. It has remarkable energy-saving effect if the fishing style of trawling is replaced by light-seine fishing, and the gathering-fish lamps of metal halide lamps or incandescent lamps are replaced by LED light sources. The conversion of the trawlers to light-seine vessel and widespread use of LED light sources will lead to cut down energy consumption and increase the economic benefits. Based on rough calculation, it can make Chinese fisherfolk increase income about hundreds of millions of dollars and reduce more than millions of tons CO2 emission if the conversion of the trawlers to light-seine vessel and the replacement of metal halide lamps or incandescent lamps to LED light sources can reach 20% of all. Moreover, LED light source can use for general lighting purpose in marine fishery. All of these will cause the development of the correlative industries. For instance, the market demand of LED is very vast.

scholarly journals Effectiveness of Light Source on Detecting Thin Film Transistor

Crystals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 394 ◽  
Author(s):  
Fu-Ming Tzu ◽  
Jung-Hua Chou
Keyword(s):  
Thin Film ◽  
Light Source ◽  
Thin Film Transistor ◽  
Metal Halide ◽  
Light Sources ◽  
Blue Led ◽  
Optical Inspection ◽  
Metal Halide Lamps ◽  
Better Than ◽  
Halogen Lamps

Light sources tend to affect images captured in any automatic optical inspection (AOI) system. In this study, the effectiveness of metal-halide lamps, quartz-halogen lamps, and LEDs as the light sources in AOI systems for the detection of the third and fourth layers electrodes of thin-film-transistor liquid crystal displays (TFT-LCDs) is examined experimentally. The results show that the performance of LEDs is generally comparable or better than that of metal-halide and quartz-halogen lamps. The best optical performance is by the blue LED due to its spectrum compatibility with the time-delay-integration charged-coupled device (TDI CCD) sensor and its better spatial resolution. The images revealed by the blue LED are sharper and more distinctive. Since current LEDs are more energy efficient and environmentally friendly, using LEDs as the light source for AOI is very beneficial. As the blue LED performs the best, it should be adopted for AOI using TDI CCD sensors.

scholarly journals Effectiveness of Light Source on Detecting Thin Film Transistor

2018 ◽  
Author(s):  
Fuming Tzu ◽  
Jung-Hua Chou
Keyword(s):  
Thin Film ◽  
Light Source ◽  
Thin Film Transistor ◽  
Metal Halide ◽  
Light Sources ◽  
Blue Led ◽  
Optical Inspection ◽  
Metal Halide Lamps ◽  
Better Than ◽  
Halogen Lamps

Light sources tend to affect images captured in any automatic optical inspection (AOI) system. In this study, the effectiveness of metal-halide lamps, quartz-halogen lamps, and LEDs as the light sources in AOI systems for the detection of the 3rd and 4th layers electrodes of thin-film-transistor liquid crystal displays (TFT-LCDs) is examined experimentally. The results show that the performance of LEDs is generally comparable or better than that of metal-halide and quartz-halogen lamps. The best optical performance is by the blue LED due to its spectrum compatibility with the time-delay-integration charged-coupled device (TDI CCD) sensor and its better spatial resolution. The images revealed by the blue LED are sharper and more distinctive. Since current LEDs are more energy efficient and environmentally friendly, using LEDs as the light source for AOI is very beneficial. As the blue LED performs the best, it should be adopted for AOI using TDI CCD sensors.

The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Active Site ◽  
Large Scale ◽  
Thrombin Generation ◽  
Factor Viia ◽  
Dependent Manner ◽  
Antithrombotic Agent ◽  
Before And After ◽  
Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

The Influence Of The Led Luminaires Electrical Parameters On Their Correlated Colour Temperature During Operation Mode

2020 ◽  
pp. 89-96
Author(s):  
Sergei S. Kapitonov ◽  
Alexei S. Vinokurov ◽  
Sergei V. Prytkov ◽  
Sergei Yu. Grigorovich ◽  
Anastasia V. Kapitonova ◽  
...  
Keyword(s):  
Operation Mode ◽  
Light Sources ◽  
Electrical Parameters ◽  
Colour Temperature ◽  
Radiation Spectra ◽  
Service Period ◽  
Close Proximity ◽  
Definition Of ◽  
Comprehensive Study

The article describes the results of comprehensive study aiming at increase of quality of LED luminaires and definition of the nature of changes in their correlated colour temperature (CCT) in the course of operation. Dependences of CCT of LED luminaires with remote and close location of phosphor for 10 thousand hours of operation in different electric modes were obtained; the results of comparison between the initial and final radiation spectra of the luminaires are presented; using mathematical statistics methods, variation of luminaire CCT over the service period claimed by the manufacturer is forecast; the least favourable electric operation modes with the highest CCT variation observed are defined. The obtained results have confirmed availability of the problem of variation of CCT of LED luminaires during their operation. Possible way of its resolution is application of more qualitative and therefore expensive LEDs with close proximity of phosphor or LEDs with remote phosphor. The article may be interesting both for manufacturers and consumers of LED light sources and lighting devices using them.

Sign in / Sign up

Export Citation Format

Share Document