Single phase brushless motor with a core

Claim 1

In a cored single-phase brushless motor of the type which includes a field magnet as a rotor having 2P (P is an integer equal to or greater than 1) driving alternate north and south magnetic pole zones, and a stator armature core disposed in an opposing relationship to said field magnet with an air gap left therebetween and having a plurality of armature coils wound thereon, the improvement wherein either the north pole zones or the south pole zones of said driving field magnet have an angular width equal to an electrical angle of about 120 degrees while the other pole zones have an angular width equal to an electrical angle of about 240 degrees, and said stator armature core has 3n (n is an integer equal to or greater than 1) equidistantly spaced stator poles having an angular width equal to an electrical angle of about 120 degrees, said armature coils including first n armature coils for the phase A wound on one or those of said stator poles which are formed at a position or positions of an electrical angle of about m·360·a (m is an integer equal to or greater than 0 and a is an integer equal to or greater than 1) degrees, second n armature coils for the phase B wound on one or those of said stator poles which are formed at a position or positions circumferentially spaced by an electrical angle of about n·(360·b-240) (b is an integer equal to or greater than 1) degrees from the stator pole or poles on which said armature coil or coils for the phase A are wound, and third n armature coils for the phase C wound on the remaining one or ones of said stator poles which are formed at a position or positions circumferentially spaced by an electrical angle of about n·(360·c-240) (c is an integer equal to or greater than 1) degrees from the stator pole or poles on which said armature coil or coils for the phase A are wound, said brushless motor comprising an electric circuit for successively energizing the n armature coils for the phase A, the n armature coils for the phase B and the n armature coils for the phase C for an electrical angle of 120 or about 120 degrees.