| 摘要 |
PROBLEM TO BE SOLVED: To provide a brushless motor which does not require a special position detection sensor for detecting the rotational position of the rotor.SOLUTION: A brushless motor 19 including a stator 21 for forming a rotating magnetic field when currents are supplied to armature coils 21a, 21b, 21c, and a rotor 22 having a permanent magnet 22b and being rotated by the rotating magnetic field is further provided with a drive unit 33 for controlling the number of revolution of the rotor 22 by performing field-weakening control, and a drive unit 33 for estimating the rotational position of the rotor 22 based on the voltages induced in the armature coils 21a, 21b, 21c when controlling the number of revolution of the rotor 22 by performing field-weakening control. |
