How to calculate the power consumption and cable of LED display?
Visit：2938 Date：2019-04-16
Regarding the problem of LED display power consumption and cable cross-sectional area, this article has specially compiled this knowledge. We calculate the electricity consumption of an electrical product, which is calculated by its electric power, that is, how much "work" the electric appliance makes per hour, and this work is obtained by multiplying the current by the voltage.
However, in actual use, the general calculation of power load is divided into two types, one type of resistive load and one type of inductive load. How to calculate the power consumption and cable of the led display?
For the resistive load calculation formula: P = UI, that is, power = voltage × current
For the calculation of the inductive load: P = UIcos ф, ie power = voltage × current × power factor
Our LED display is used by transformer switching power supply and is an inductive load. The power factor of its switching power supply load is cosф = 0.75. Different inductive load power factor is different, we can calculate the power factor cosφ of 0.8 when calculating the LED display power supply switching power supply.
The LED display drive voltage is 5V, and the drive current is less than 20mA. The maximum power calculation method of the screen is as follows (based on 100 square meters):
1. The specifications of the outdoor LED display are: the dot spacing is 10mm, the dot density is 10000 dots/square meter, and each dot (pixel) is composed of 1 red 1 green 1 blue 3 LED lights, and the scanning mode is 1/4 scan.
2, the display power per square meter display: P = 10000 (point) X 3 (particles) X 5 (volts) X 0.02 (ampere) X 1/4 (scan) = 750 (watts)
3, led display screen full screen power consumption: P = 750 (watts) X100 (square meters) = 75KW
4, the entire screen power consumption:
Because the electrical energy is converted to each other, the general power is increased by 10% based on the theoretical calculation. The auxiliary equipment (air conditioner, fan, lighting, power amplifier, etc.) also generates a certain power consumption. The power consumption of the auxiliary equipment of this screen is calculated according to the actual amount (we calculate the following formula temporarily calculated according to 5KW).
P= 75KW+7.5 KW +5KW =87.5KW
Therefore, the total power of the led display is 87,500 watts, and the maximum current is:
I=P/Ucosф=87500(Watts)÷220*0.8(cosф)=318(A)
However, under normal working conditions, the LED display LED cannot be lit for a long time at the same time, so the user's power supply capacity can be used as a common coefficient formula with a common coefficient of 0.5. Therefore, the above calculation should be rewritten as:
I=P*Common coefficient/Ucosф=(82500(Watts)*0.5+5000(Watts))÷220*0.8(cosф)=168(A)
In other words, the total current value of this screen is 168A. Because the instantaneous current is relatively large when the LED display starts, the total gate air switch cannot use the three-phase 168A switch. The air switch of 318A should be used, and 400A can be selected. Many of our peer engineers are accustomed to directly calculate the total power of the large screen by the number of switching power supplies on the whole screen. This method is not standard. Some manufacturers reduce the number of switching power supplies in order to reduce the cost, and finally lead to incorrect power calculation.
5, average power consumption:
The power consumption is different because the content is different. For example, if you play commercials, the colors are rich and the white is mostly. The average power consumption is 50% of the maximum power consumption. When playing simple graphics such as text, most of the screens are black, and the average power consumption is 10% of the maximum power consumption. According to normal advertising statistics, the average average power consumption is 40% of the maximum power consumption.
The general copper wire safety calculation method is:
The safe current carrying capacity of the 2.5 square millimeter copper power cord --28A.
The safe current carrying capacity of the 4 square millimeter copper power cord - 35A.
The safe current carrying capacity of the 6 square millimeter copper power cord - 48A.
The safe current carrying capacity of the 10 square millimeter copper power cord - 65A.
The safe current carrying capacity of the 16 square millimeter copper power cord - 91A.
The safe current carrying capacity of the 25 square millimeter copper power cord - 120A.
If it is an aluminum wire, the wire diameter should be 1.5-2 times that of the copper wire.
If the copper current is less than 28A, it is safe to take 10A per square millimeter.
If the copper current is greater than 120A, take it at 5A per square millimeter.
The current through which the cross-sectional area of the wire can normally pass can be selected according to the total number of currents that it needs to conduct. Generally, it can be determined by following the jingle:
Tenth Five-Year, One-hundred-two, Two-Five-Three-Five-Four-Five, and two and a half times, the copper wire is upgraded.
To explain to you, it is 10 square meters of aluminum wire, the square millimeter is multiplied by 5, if the copper wire, it will rise a file, such as 2.5 square copper wire, it will be calculated according to 4 square. More than one hundred Both cross-sectional area multiplied by 2, twenty-five squares or less multiplied by four, thirty-five squares or more multiplied by three, and both 95 and 95 squared are multiplied by 2.5, so a few words should be well remembered,
Description: Can only be used as an estimate, not very accurate. In addition, if you remember the copper wire below 6 square millimeters in the room, it is safe to not exceed 10A per square current. From this point of view, you can choose 1.5 square copper wire or 2.5 square aluminum wire.
Within 10 meters, the conductor current density of 6 A/mm 2 is suitable, 10-50 m, 3 A/mm 2 , 50-200 m, 2 A/mm 2 , and less than 1 A/mm 2 over 500 m. From this perspective, if not very far, you can choose 4 square copper wire or 6 square aluminum wire. If it is really a distance of 150 meters (not to mention whether it is a tall building), it must use 4 square copper wire.
The impedance of a wire is proportional to its length and inversely proportional to its wire diameter. Please pay special attention to the wire and wire diameter of the input and output wires when using the power supply. In order to prevent the current from being too high, the wire is overheated and an accident is caused.