The stranded wire is realized by the uniform angular speed rotation of the stranded single wire around the stranded wire axis and the uniform forward movement of the stranded wire. Copper and aluminum wires are commonly used. Copper and aluminum wires can be twisted into wire cores of different specifications, sections and types of wires and cables. It is suitable for occasions with high working frequency and excessive skin effect and proximity effect loss of single strand wire. The use of stranded wire can reduce the operating temperature. Compared with single strand wire with the same cross-sectional area, the stranded wire has higher mechanical property and flexibility.