Hair dryer is mainly used for hair drying and shaping, but it can also be used for local drying, heating and physiotherapy in laboratory, physiotherapy room, industrial production, art and other aspects. According to the type of motor it uses, it can be divided into AC series excitation type, AC shaded pole type and DC permanent magnet type. The advantages of series blower are large starting torque, high speed, suitable for manufacturing high-power blower; the disadvantages are high noise, commutator has certain interference to telecommunication equipment. The advantages of shaded pole blower are low noise, long service life and no interference to telecommunication equipment; the disadvantages are low speed, poor starting performance and heavy weight. The advantages of permanent magnet blower are light weight, high speed, simple manufacturing process, low cost and low price.