| 摘要 |
PROBLEM TO BE SOLVED: To provide a brushless DC motor which does not need excessive wirings and terminals, has a simple construction, facilitates the size reduction and has a protective device. SOLUTION: A three-phase power is supplied from a motor driving circuit unit 33 to a motor unit 32 through power supply lines 34u, 34v and 34w, and the armature windings 35u, 35v and 35w of the motor unit 32 are successively excited to turn a rotor. Induced voltages which are induced in the armature windings 35u, 35v and 35w by the rotation of the rotor are detected to detect a rotor position. The current application phases of the armature windings 35u, 35v and 35w are switched in accordance with the detected result to drive the rotor to rotate continuously. Further, a protective device 43 which is made to operate by a temperature is inserted in series in the middle of the power supply line 34u and, when the induced voltage of the armature winding 35u is not detected by the opening operation of the protective device 43, the power supply to the motor unit 32 is discontinued. With this constitution, the simple construction and the size reduction can be realized easily. |
