Two-phase permanent-magnet electric rotating machine

DETAILED DESCRIPTION In order to achieve the above object, according to a first aspect of the present invention, the two-phase permanent-magnet electric rotating machine comprises: a stator having 2.
sup.
n main poles (n being an integer satisfying a condition n.
gtoreq.
2) provided circumferentially so as to project inward centripetally from an inner circumferential surface of a substantially annular magnetic body, the stator having exciting windings wound on the main poles respectively, each of the main poles having on its end portion a predetermined number of magnetic teeth; and a cylindrical rotor having a plurality of permanent magnets formed in a manner so that N (north) and S (south) poles equal in number of the permanent magnets are alternately circumferentially disposed, the rotor being supported so as to be rotatable relative to the stator with a predetermined air gap between surfaces of the main poles and surfaces of the permanent magnets; wherein the main poles are arranged in a manner so that 2.
sup.
(n-1) alternate ones of the main poles are made to be in-phase and that a half of the in-phase main poles have a polarity which is opposite to a polarity of the other half of the in-phase main poles.
Preferably, in the above two-phase permanent-magnet electric rotating machine, the value of n of the 2.
sup.
n main poles is 2 and the number of the magnetic pole pairs of N and S of the rotor is 4m.
+-.
1 (m being an integer satisfying a condition m.
gtoreq.
1).
Preferably, in the above two-phase permanent-magnet electric rotating machine, a back yoke formed from a magnetic substance is provided on the permanent magnet rotor on its one side opposite to its other side facing the stator, and the windings and connections thereof are formed in a manner so that the in-phase main poles of the stator are made alternately different from each other in polarity.
According to a second aspect of the present invention, the inner-rotor or outer-rotor type two-phase permanent-magnet electric rotating machine comprises: a stator including a stator iron core made from a magnetic substance in a predetermined shape having a disc portion and 2