Patent ID: 6278248
Filing Date: 2001-08-21
Classification: F04D,H02K,H02P

Abstract:
A brushless direct current motor fan driven by an alternating current power source, the brushless direct current motor fan comprising:a rotor including a shaft rod and a rotor permanent magnet with at least one set of north pole and south pole;a stator including a plurality of pole plates and a coil, the stator including a central hole, for an axle tube to be sleeved on;an axle tube, a bearing mounted inside for pivotally supporting a shaft, the axle tube being extended through the central hole of the stator;a drive circuit board including a sensor element and a plurality of electric elements to constitute a drive circuit; anda fixed plate including a plurality of electric elements mounted thereon to constitute a conversion circuit and including a power line adapted to be electrically connected to the alternating current power source;the alternating current being converted into a direct current power source after rectification, filtering and regulation by the conversion circuit, the direct current power source driving the drive circuit and cooperating with the sensor element that detects a change in polarity of the permanent magnet to thereby provide alternately conducted current with positive/negative polarity to the coil of the stator, thereby generating an alternating magnetic field for driving the rotor.