| 摘要 |
A brushless motor provided with a stator (21) having armature coils (21a, 21b, 21c), a rotor (22) caused to rotate by a rotating magnetic field, and a switching element (30a), wherein the brushless motor is characterized by: having a rotation number control unit (33) for switching between a low-speed mode and a high-speed mode; in the low-speed mode, the rotation number control unit (33) supplying current at a predetermined energization timing to the armature coils (21a, 21b, 21c), and controlling the number of rotations of the rotor (22) by controlling the duty ratio; and, in the high-speed mode, the rotation number control unit (33) supplying a current to the armature coils (21a, 21b, 21c) at an energization timing more advanced than the energization timing in the low-speed mode, and thereby performing magnetic-field weakening control that makes the rotating magnetic field weaker than in the low-speed mode and controlling the number of rotations of the rotor (22). |
