Six square meters of copper wire is equivalent to ten square meters of aluminum wire. Aluminum wire diameter than copper wire, the same stator slot aluminum wire will not fit. The resistivity of copper wire is 0.017 and that of aluminum wire is 0.028. The exchange section ratio between copper wire and aluminum wire is 0.79:1, and the current flow per unit area is also different. Copper wire can pass 5-8a current per square millimeter, while aluminum wire is much less, about 3-5a.

　　In addition to the different closure amount and raw materials of the copper and aluminum wires of explosion-proof motors, the main differences are as follows: the aluminum wires are lighter in quality, relatively cheap, and have poor mechanical strength. The aluminum wires are extremely easy to be oxidized at the end of the connection line, and after oxidation, temperature rise and poor contact will occur at the end of the connection line, leading to frequent faults (power failure or wire breakage). Other aluminum is not easy to weld, small strength, low melting point, easy oxidation, high temperature rise, large cost. According to :p=I*I*R, we know that at the same current, large resistance R consumes large power, so aluminum wire is not as good as copper wire.