LED Street Lights Have A Certain Level Of Dust And Water Resistance
The heat dissipation of LED street lamps is one of the key problems that need to be solved. It is not only directly related to the luminous efficiency of LEDs in actual work, but also because LED street lamps require high brightness and heat generation, and the outdoor environment is more demanding. If the heat dissipation is not good It will directly lead to rapid aging of the LED and lower stability. Because road lamps used outdoors should have a certain level of dust and water resistance (IP), good IP protection often hinders the heat dissipation of LEDs. Solving these two contradictory problems that both have to be solved is an important aspect that should be paid attention to when designing road lamps. In this respect, it is also the most unqualified and unreasonable situation when LEDs are used in road lamps in China. The unqualified and unreasonable situations in domestic use basically include:
(1) A heat sink is used for the LED, but the design of the terminal and the heat sink of the LED connection cannot reach IP45 and above, and cannot meet the requirements of the GB7000.5/IEC6598-2-3 standard.
(2) Adopt ordinary road lamp housing and use matrix LED in the light emitting surface of the lamp. Although this design can meet the IP test, the temperature of the inner cavity of the lamp will increase due to the lack of ventilation in the lamp. At 50°C to 80°C, under such high working conditions, the luminous efficiency of the LED is unlikely to be high, and the service life of the LED will also be greatly reduced. In fact, there is an obvious unreasonable situation.
(3) The instrument fan is used in the luminaire to dissipate the LED and the radiator. The air inlet is designed under the luminaire to prevent rainwater from entering, and the air outlet is designed around the downward LED light source. This can also effectively prevent rainwater from entering. In addition, the radiator and the LED (light source cavity) are not in the same cavity. If this design is done well, it can pass smoothly according to the IP test requirements of the lamp. This solution not only solves the heat dissipation problem of the LED, but also meets the requirements of the IP level at the same time. However, this seemingly good design is actually obviously unreasonable. Because in most road lighting applications in my country, the amount of fly dust in the air is relatively large, sometimes reaching a large amount (such as sandstorms). This kind of lighting is used for a period of time under normal conditions (about three months to Half a year), the gap of the internal radiator will be filled with dust, which will greatly reduce the effect of the radiator. Finally, the service life of the LED will be significantly shortened due to the high operating temperature. The disadvantage of this scheme is that it cannot be used consistently and well.
