Brushless dc motor with improved starting
    1.
    发明公开
    Brushless dc motor with improved starting 失效
    启动无刷直流电机。

    公开(公告)号:EP0141479A1

    公开(公告)日:1985-05-15

    申请号:EP84300856.6

    申请日:1984-02-10

    发明人: Reffelt, James

    IPC分类号: H02K29/08

    CPC分类号: H02K29/08

    摘要: A brushless DC motor of the kind that includes a relatively large rotor permanent magnet (14) magnetized radially in segments around its circumference to provide alternate segments oppositely magnetized has a stator (12) magnetic structure with two dissimilar pole pieces (46,47) in flux conducting relation to a pair of windings. A first of the pole pieces (46) presents a face to the outer surface of the annular magnet across an air gap. A second pole piece (47), which may be somewhat further from the outer surface of the annular magnet (14), at the opposite end of the windings, presents only a norrow edge surface (62) facing generally in the direction of the magnet. The modified pole piece (80) is L-shaped or U-shaped, having one or two legs (82, 83) respectively, projecting from the coil support structure generally circumferentially with respect to the magnet. The legs (82, 83) taper towards their ends more remote from the coil (41) support structure and form broader upper and lower surfaces more nearly perpendicular the axis of magnet rotation than the narrow edge surface or surfaces facing the magnet across the air gap.