GB872429A - Miniature synchronous motor - Google Patents

Abstract

872,429. Electric motors. LICENTIA PATENT-VERWALTUNGS-G.m.b.H. Jan. 6, 1958 [Jan. 8, 1957], No. 449/58. Class 35. A self-starting miniature synchronous motor comprises a multi-polar stator having 2n poles 98 so energized that poles if opposite succeed one another, and mounted on a rotatable shaft, not shown, a multi-polar rotor 99 consisting of a high coercivity ferro- or ferri-magnetic ring or disc on the circumference of which are formed by radial magnetization (n - i) poles N of one polarity and (n - k) poles S of the other polarity, i and k being whole positive numbers of which i is less than k. The motor is rendered selfstarting by omitting two rotor south poles S (i=0, k=2) the remaining poles being arranged in the symmetrical groups shown, all poles have a width subtending substantially the same angle, and, if formed by the ring, the interior may have injection moulded therein a non- ferromagnetic synthetic plastic material forming the rotor shaft hub and possibly the shaft itself. The stator may comprise an energizing coil between two metal end cover-plates extending normal to the axis and having axially-bent striplike portions forming the poles.