Bought the power cord of my friends know the size of the power cord to use the square that is the power cord of the size of the circular cross-section of an oral language, often eliminating the need for units of mm, ie, square millimeters. According to experience, when the grid voltage is 220V when the per square copper wires, power lines can carry power 1-1.5 kW. Each square aluminum conductor power lines can carry power 0.6-1 kW. Short-range transmission generally copper per square foot can carry the 3A to 5A current. Cooling conditions are good to take 5A / mm2, heat dissipation is not good to take 3A / square millimeter.
     
       Following the conversion of all power lines, and I hope useful to everyone.
            Conversion method:
            Know that the square of the power cord, and the formula of calculation of the radius of the wire of circular area calculation:
            The square of the wire and square (mm2) = pi (3.14) x wire radius (mm).
            Know the power cord to the square of the diameter of the calculation of line, such as:
            Wire diameter of 2.5 square wire is: 2.5 ÷ 3.14 = 0.8, then prescribing drawn to 0.9 mm, wire diameter of 2.5 square line is: 2 × 0.9 mm = 1.8 mm.
            Know the diameter of the power cord, calculate the square of the wire of circular area of the formula to calculate:
            The square of the power cord = pi (3.14) × line diameter squared / 4
            Cable the size of the square of the nominal, multi-strand wire is the wire cross-sectional area and of each root.
            Cable cross-sectional area of ​​the formula:
            .7854 × wire radius (mm) square x number of shares
            Such as 48 shares (0.2 mm) per wire radius of 1.5 square line:
            0.785 × (0.2 × 0.2) × 48 = 1.5 square
 

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