built in led fluorescent tube lights lamp with high brightness white led light source
Led fluorescent tube lights lamp is the use of CREE and AOD super bright LED white light as the light source, the shell is acrylic / aluminum alloy. led fluorescent tube lights lamp installation is relatively simple, it is divided into two kinds of internal and external power supply, the power built-in led fluorescent tube lights lamp installed, the original fluorescent down to replace the led fluorescent tube lights lamp, and ballast and starter removed, so that 220V AC Mains directly to the LED lights can be added at both ends. Power supply External led fluorescent tube lights lamp is generally equipped with a dedicated lamp holder, replace the original can be used.At present, almost all of the led fluorescent tube lights lamp on the market are built-in power supply. The so-called built-in means that the power can be placed inside the lamp. The biggest advantage of this built-in can be made directly replace the existing fluorescent tubes, without having to make any changes to the original circuit. So the shape of the built-in power supply is usually made into strips, so that into the semi-circular lamp to go. There are two built-in power supply, one non-isolated (Figure 1), one is isolated (Figure 2).Non-isolated refers to the led load and 220V input terminal has a direct connection, so there is the risk of electric shock to touch the load. 220V and aluminum shell only between the very thin insulating layer of aluminum isolation, usually not easy to CE and UL certification.Isolated refers to the input and output isolation transformer isolation, this transformer may be frequency or high frequency. But can isolate the input and output. The risk of electric shock can be avoided. Also easy to pass CE or UL attestation.First, the built-in power led fluorescent tube lights power consumptionThe biggest advantage of using built-in power supply is that you can replace the existing fluorescent lamps without having to make any changes to the original wiring. So built-in this advantage is not also pay a certain price? Indeed, but the price is not small. This is from the ordinary fluorescent lamp ballast structure Speaking:We know that the most common fluorescent lamp is the use of a series of core inductance and a parallel starter (Figure 3a). For this circuit in the direct replacement with led fluorescent tube lights lamp, as long as the unplug the starter on it. But because the core inductance is still connected in series in the circuit, so it still brings nearly 6.4W (Philip) to 10W (domestic) loss, the result of this part of the additional loss to greatly reduce the power saving LED efficacy. For example, originally a 20W led fluorescent tube lights lamp can replace a 36W fluorescent lamp, built-in non-isolated 20W led fluorescent tube lights lamp, for example, the measured results are as follows.In other words, the direct result of the replacement is greatly reduced efficiency, domestic ballast for the inductance, efficiency is only 56.2%. Only 6.8W than conventional fluorescent lamp power saving.This makes the energy-saving efficiency LED tube greatly reduced, so that the contract energy management (EMC) difficult to implement.Second, heat and lifeAnother major drawback of built-in power supply is low life. Because the power must be placed in the aluminum tube, so the aluminum tube can not be made into the form of fins, but only ordinary half-cylindrical, at most, on the surface with some very shallow strip groove (Figure 4) .The surface area of this semi-cylinder is: 2πR * h / 2 = πR * h. For the T8 lamp, its diameter is 26mm, so the radius is 13mm. 1.2 m T8 tube, the surface area: π * 1.3 +120 = 490cm2, we know that the LED heat sink surface area usually requires 60cm2 / W. , So this semi-aluminum tube can only be about 8W of heat. The T8 led fluorescent tube lights lamp is usually the input power of 20W, assuming the luminous efficiency of LED is only 20%, then 16W of input power into heat. And now can only be dispersed 8W of heat, but also 8W of heat can not be dispersed, the result is to make the LED junction temperature rise, shorten life expectancy.
Not only that, because the power built-in, the power of the heat will be added to the tube, assuming the power efficiency of 88%, so there is 2.4W of heat should be dispersed, equivalent to an increase of 30% of the heat, that is a total of 10.4W of power can not be distributed out. Making the LED heat dissipation has increased a difficult, or that makes LED life is more shortened. Moreover, the length of the power supply is about one-fifth the length of the lamp, the heat generated by the power supply is also concentrated in this section, making the LED near the power of the baking by the hotter, and therefore life than other parts of the LED Short, the lamp in the damaged, close to the power of a black out first. It can be considered that the life of the built-in power supply led fluorescent tube lights lamp will not be higher than 10,000 hours.And the power into the tube inside, the power itself has to bear the high temperature generated by the LED, which greatly reduces the life of electrolytic capacitors in power, it reduces the life of the entire lamp.Third, the use of costBecause the built-in power LED lamp life of only 10,000 hours, and 50,000 hours of external power compared to the use of its cost is clearly 5 times higher. Not only that, in the course of use, whether it is damaged LED, or power is damaged, usually with the two should be discarded. The external power supply led fluorescent tube lights lamp, which can be lost which lost.In addition, built-in power supply also increased the cost of e-waste recycling. Because the power part must be removed and then dealt with separately.Fourth, other functionsExternal power supply, not only high efficiency, long life, but also can increase the manual dimming or automatic dimming and other special features, these are built-in can not match!