| 摘要 |
PROBLEM TO BE SOLVED: To generate brake torque which simplifies and solidifies the structure and stops a rotor without fail at start. SOLUTION: An ordinary outer rotor type of brushless DC motor 20 rotates, by switching the current supplied to a three-phase coil 25 from an inverter 31, according to the rotation. When a rotational speed detector 34 judges the stoppage of the motor, the contact r of a relay is switched on, and DC exciting currents flow to V and W phase of coils 25 from a low-voltage switching power circuit 32 through a DC excitation supply line LDc. Therefore, a rotor magnet is attracted by the magnetic attraction generated by the DC excitation current, and brake torque to keep the rotation state of the rotor is generated. |
