| 摘要 |
<P>PROBLEM TO BE SOLVED: To immediately return an electric fan motor to a stable condition in unlocking the electric fan motor with a simple structure. <P>SOLUTION: Motor current from a battery 30 is supplied to the electric fan motor 10 by a switching circuit 110 as a switching means. The switching circuit 110 is driven and controlled with predetermined PWM control signal by a drive control circuit 120 as a drive control means. Duty of PWM control signal is changed according to change of temperature at the switching circuit 110 and change of voltage between terminals of the electric fan motor 10. Drive at lower duty than specified duty is continued even when the electric fan motor is locked, and duty is returned to the specified duty in unlocking the electric fan motor. <P>COPYRIGHT: (C)2009,JPO&INPIT |
