Rotor of an electrical motor comprising embedded permanent magnets

A pair of nonmagnetic portions (24) are formed in a rotor core (21) at opposite ends of each pole, formed by a permanent magnet (22). Given that a circumferential pitch of teeth cores (11b) is Äs and an opening angle is the angle defined with respect to the axis of said rotor (20) between a first point at which the radial width of a first one of the pair of magnetic path portions (27) is a minimum and a second point at which the radial width of a second of said pair of magnetic path portions (27) is a minimum, ¸ (n + Y) × Äs (n: integer larger than 0) is met. Y = 0.5 is set when the stator has a distributed winding, and Y = 0.9 - 1.2 is set when the stator has a concentrated winding. The magnet (22) forming one pole is divided into two parts, and a bridge portion (28) is formed between the two divided magnet parts (22).