A motor arranged to rotate in only one rotational direction, comprising: a stator; and a rotor rotatably arranged inside the stator, wherein the rotor comprises a rotor body, a permanent magnet group provided to the rotor body to generate a magnetic field, and a flux barrier group to interrupt magnetic flux, wherein at least one of the rotor body, the permanent magnet group and the flux barrier group are asymmetrically formed with respect to a centre of poles of the rotor, wherein a distance between an outer circumferential surface of the rotor body and a centre of the rotor body varies, wherein a position on the outer circumferential surface defining the longest distance between the outer circumferential surface and the centre of the rotor body is spaced a predetermined angle from the centre of poles of the rotor in the only one rotational direction, wherein the permanent magnet group comprises a first permanent magnet disposed in the rotor body such that a magnetic field is created in a radial direction of the rotor body and second and third permanent magnets (122b, 122c) asymmetrically disposed at opposite ends of the first permanent magnet, wherein the second permanent magnet is positioned at a side of the first permanent magnet facing in a direction opposite to the one rotational direction and the third permanent magnet is positioned at the other side of the first permanent magnet facing in the one rotational direction, the third permanent magnet being longer and creating a greater magnetic field than the second permanent magnet, wherein the flux barrier group comprises a first magnetic flux barrier, a second magnetic flux barrier, a third magnetic flux barrier and a fourth magnetic flux barrier, wherein the first and third magnetic flux barriers (123a, 123c) are disposed at one end of the second permanent magnet, the second magnetic flux barrier is disposed at one end of the third permanent magnet, and the fourth magnetic flux barrier is formed adjacent to the first and third flux barriers and close to the outer circumference of the rotor body, the fourth magnetic flux barrier being positioned at a side of the first and third magnetic flux barriers that face in the rotational direction; and wherein the first and second magnetic flux barriers (123a, 123b) are of corresponding size to each other, and the third magnetic flux barrier has a size corresponding to the difference in size between the second permanent magnet and the third permanent magnet, such that the first and third magnetic flux barriers (123a, 123c) intercept more flux than the second magnetic flux barrier. a stator; and a rotor rotatably arranged inside the stator, wherein the rotor comprises a rotor body, a permanent magnet group provided to the rotor body to generate a magnetic field, and a flux barrier group to interrupt magnetic flux, wherein at least one of the rotor body, the permanent magnet group and the flux barrier group are asymmetrically formed with respect to a centre of poles of the rotor, wherein a distance between an outer circumferential surface of the rotor body and a centre of the rotor body varies, wherein a position on the outer circumferential surface defining the longest distance between the outer circumferential surface and the centre of the rotor body is spaced a predetermined angle from the centre of poles of the rotor in the only one rotational direction, wherein the permanent magnet group comprises a first permanent magnet disposed in the rotor body such that a magnetic field is created in a radial direction of the rotor body and second and third permanent magnets (122b, 122c) asymmetrically disposed at opposite ends of the first permanent magnet, wherein the second permanent magnet is positioned at a side of the first permanent magnet facing in a direction opposite to the one rotational direction and the third permanent magnet is positioned at the other side of the first permanent magnet facing in the one rotational direction, the third permanent magnet being longer and creating a greater magnetic field than the second permanent magnet, wherein the flux barrier group comprises a first magnetic flux barrier, a second magnetic flux barrier, a third magnetic flux barrier and a fourth magnetic flux barrier, wherein the first and third magnetic flux barriers (123a, 123c) are disposed at one end of the second permanent magnet, the second magnetic flux barrier is disposed at one end of the third permanent magnet, and the fourth magnetic flux barrier is formed adjacent to the first and third flux barriers and close to the outer circumference of the rotor body, the fourth magnetic flux barrier being positioned at a side of the first and third magnetic flux barriers that face in the rotational direction; and wherein the first and second magnetic flux barriers (123a, 123b) are of corresponding size to each other, and the third magnetic flux barrier has a size corresponding to the difference in size between the second permanent magnet and the third permanent magnet, such that the first and third magnetic flux barriers (123a, 123c) intercept more flux than the second magnetic flux barrier.