"220V AC Cooling Fan" That is the main motor stator and rotor. Motor stator windings for four more symmetrical distribution, ie a 90 ° angle between each other, unlike the three-phase asynchronous motors into each other in a distributed fashion star 120 ° angle. There have been stuck on the rotor magnetized permanent magnet, typically magnetic rubber or rubber ring. "220V AC Cooling Fan" is mainly driven by the digital control circuit chip, the rotor position sensor and power-driven components. Digital control chip DSP (digital auxiliary processor), and other common IC such as TMS320. Rotor position sensor Hall components commonly used to determine the position of the rotor magnet rotor according to changes in the magnetic field direction. "220V AC Cooling Fan" power drive assembly includes a PWM control circuit and the power tube, power tube usually MOSFET, the driving coil stator winding working under the control of the PWM driving signal.