PURPOSE:To reduce a noload magnetic flux amount and to obtain a motor having series winding characteristic by increasing an angle from an electric neutral axis to the demagnetization end of a permanent magnet disposed at the demagnetization side. CONSTITUTION:When an armature coil 4 is conducted through brushes 10, an armature reaction magnetomotive force is operated at a field pole. An increasing magnetic force is operated at the left side and a decreasing magnetic force is operated at the right side at the central X-axis of the pole as a boundary with the m axis of the electric neutral axis of the brush 10 as a reference, and gradually increased from the X axis toward the increasing magnetic end 13 of an auxiliary pole 8 and the decreasing magnetic end 11 of a permanent magnet 11. However, the angle thetam1 of the permanent magnet from the X axis of the magnetic center to the end 11 is reduced due to the large space angle theta2 between the end of the magnet 9 and the m axis of the neutral axis disposed with the brush 1. Accordingly, its enclosure becomes a small value, the decreasing magnetic force due to the armature reaction Ha becomes small value due to the fact that the radial thickness of a conventional permanent magnet 9 becomes the same as Lm, thereby enhancing the noload rotating speed.
展开▼
