Technology | power grounding of LED large screen can play a key role China lighting network

Core components of LED large screen is composed of LED lights and IC driver, because the LED is very sensitive to electrostatic, electrostatic will lead to breakdown, light-emitting diodes (leds) so in the process of installation of LED large screen, it must be grounding measures, to avoid the risk of death lamp. The working voltage of LED large screen at around 5 v, generally under the working current of 20 ma, determines its operating characteristics of the LED in the face of electrostatic and abnormal voltage or current shock resistance is very fragile. This needs us in the process of the production and use to recognize this, and give enough attention and take effective measures to protect the LED large screen. And power grounding is LED large screen commonly used a protection method. Why the power supply to ground? This related to the operation mode of the switch power supply, LED large screen is a kind of switch power supply, rectifier, pulse modulation, through filtering the output rectifier, filter and a series of means to communicate ( AC） 220 v mains is converted into dc ( DC) 5 v dc power supply stable output of a device. In order to guarantee the stability of the power supply AC/DC conversion in AC220V power supply manufacturer in accordance with the national 3 c compulsory standards in the design of circuit at the input, the line of fire to ground jumper an EMI filter circuit. To ensure the stability of AC220V input, so all the power in the work is filter leakage, leakage current of a single power supply 3. About 5 ma. Leakage voltage of about 110 v. In the case of LED large screen earthing, leakage current can not only cause damage or bulbs burn out chip. If you use more than 20 power, accumulate the leakage current of 70 ma. Enough to cause leakage protector action, to cut off the power supply. This is why the LED large screen can't use the cause of the leakage protector. If you don't pick up the leakage protection and LED large screen not grounding, power superposition of current will exceed human body safety, the 110 v voltage is sufficient to cause death! And after grounding, shell voltage close to 0 to the human body. Show that there is no potential difference between the power and the human body, are imported the earth leakage current. So, the LED large screen must be grounded. But there are often customers using the wrong grounding method for LED large screen, common one, think outdoor pillar type structure of the column bottom is connected with the earth, so don't need to do the LED large screen grounding; 2, think power is locked on the box body, and between the box body are mutually connected with lock and structure, so structure grounding means power also. Pillar of the two kinds of wrong, is connected to the foundation anchor bolt to keep, and the inside of the anchor bolt is embedded in the concrete, the resistance of the concrete in the range of 100-500 Ω, grounding resistance is too high will lead to leakage current discharge time remaining. Body surface of spray paint, and paint is a poor conductor of electricity, will lead to the poor contact or grounding resistance of grounding of the rise, LED large screen body likely spark interference signal. As time goes on, the LED large screen frame or structure surface will appear oxidation and corrosion, fixing parts such as screws also gradually loosened as the temperature changes in heat bilges cold shrink. Will lead to the LED large screen structure grounding effect weakened and even complete failure. Form a safety hazard. Cause the leakage flow of electric shock, damage to the chip interference, such as the occurrence of safety accidents. Then, the standard of ground should be how? Power input end of the three terminals, wire terminals, zero line terminal and earthing terminal. Correct grounding practice is to use a special yellow green double color line will all power ground wire terminals concatenated and lock, and then lead to connect to the ground. If the site no earthing terminal, can be connected to the iron water pipe or iron pipes buried with the earth and keep good contact with the ground line, in order to ensure good contact on such natural grounding body welding terminals, then put the earth wire lock on the terminal, shall not be bound to connect. But the gas pipelines and other inflammable and explosive and shall not be used. Or buried grounding system at the scene. Grounding body Angle steel or steel tube can be used, horizontal or vertical embedded in the earth as a simple circuit, ground should choose the middle of nowhere, so as to avoid pedestrians or vehicles damage grounding body. When grounding earthing resistance must be less than 4 ohm, to ensure the timely release of leakage current. It is important to note that the grounding end when discharge lightning current due to the spread of the earth current needs certain time, in a short period of time will lead to the ground potential rise, if the LED large screen earthing grounding side, connected to the ground potential is higher than the LED large screen, lightning current will be along down this ground wire transfer to the LED screen, cause equipment damage. So the LED large screen this protective earthing shall not join to the grounding end, protective earthing end must distance lightningproof grounding end more than 20 meters. Prevent the ground potential.

YanZhiXiang

the LED screen mesh