| 摘要 |
PURPOSE:To design to release a lock and to protect a motor and a power transistor by electrifying a core electric current to a motor controlling power transistor for a fixed period only when there is possibility of a freezing lock of a direct current motor for blower fan driving. CONSTITUTION:A speed of a direct current motor 5 driving a blower fan of an air conditioner for a vehicle is controlled through a D/A converter 12 and power transistors Tr1 and Tr2 based on an output of a microcomputer 11 which receives an input from an air quantity setting device 1a of an air conditioner operation panel 1. When a motor lock is detected through an application of terminal voltage VM between the motor and the microcomputer 11 the micro- computer 11 judges if there is possibility of a freezing lock and the motor is elec trified for a fixed period only when there is the possibility and release of the freezing lock through a selffever is carried out. |
