Hair dryers are mainly used for hair drying and plastic surgery, but they can also be used for local drying, heating and physiotherapy in laboratories, physiotherapy rooms, industrial production, art and other aspects. According to the type of motor it uses, it can be divided into AC series excitation, AC shaded pole type and DC permanent magnet type. The advantages of series blow dryer are large starting torque and high speed, which is suitable for manufacturing high-power hair dryers, and the disadvantage is that the noise is large, and the commutator has certain interference to telecommunication equipment. The advantages of shaded pole hair dryer are low noise, long life, and will not cause interference to telecommunication equipment, and the disadvantages are low speed, poor starting performance, and large weight. The advantages of permanent magnet hair dryer are light weight, high speed, simple manufacturing process, low cost, and low price.