Polyphase permanent-magnet sync motor with converter-fed stator - has alternately magnetised rotor pole pieces incorporating axial slots for presentation of higher reluctance to transverse magnetic field

摘要

The rotor poles (1) are capped with permanent magnets (3) and sepd. by slots (2) cut into a ring (5) around the shaft (4). The slots are broadened into cavities (6) in the circumferential direction and a smaller radial slot (7) is machined along the centre line of each pole to increase the magnetic reluctance for the transverse field. The longitudinal field follows a low-reluctance path through the magnetisable material of the pole pieces (8) which are of alternate polarity with sufficient cross-section to avoid unwanted saturation, and laminated but highly resistant to deformation. ADVANTAGE - Mechanical stability and rigidity are maintained even at high rotational speeds despite different transverse and longitudinal field reluctances.