1. Field of the Invention
The present invention relates to a brushless DC motor of the type in which a magnetic field of a rotor is generated by a rotor permanent magnet and a magnetic field of a stator is generated by a field magnetic coil. In particular, the present invention relates to a brushless DC motor in which the efficiency thereof is improved by providing a permanent magnetic core within a stator field magnetic coil core and by providing a boosting permanent magnet external this permanent magnetic core within the stator. The stator magnetic field is enhanced by the combination of the magnetic force of the field magnetic coil and the magnetic force of the boosting permanent magnet when the field magnetic coil is excited.
2. Description of the Related Art
In the conventional DC motor of the type in which the magnetic field of the rotor is generated by the rotor permanent magnet and the magnetic field of the stator is generated by the field magnetic coil, the efficiency is low relative the power consumption of the electric current supplied to excite the field magnetic coil to generate the magnetic field of the stator.