The IT industry which dominated by microelectronics technology, communication equipment and networks, currently is developing rapidly and the demand for special motors is increasing too. Most of these motors are permanent magnet motors, brushless DC motors, stepping motors, and single-phase motors, AC induction motors, synchronous motors etc. Fans are used everywhere in IT industry, as small as the heat dissipation impeller of the computer mainframe, as large as the air conditioner of the data center computer room, the communication base station fan, the base station heat exchanger and other motors.