| 摘要 |
PROBLEM TO BE SOLVED: To suppress the impact sound caused by a sudden application of drive force on a rotating body. SOLUTION: When the number of revolution of a motor 14 reaches the target number of revolution, a zero-crossing counter 41 and a motor up-down flag 33 are reset. Thereafter, the conducting angle of a TRIAC 22 is slowly increased until the value of the zero-crossing counter 41 reaches 6. Then, after the value of the zero-crossing counter 41 reaches 6, the conducting angle of the TRIAC 22 is made constant, and the specified amount of electric power is continuously supplied to the motor 14. When the specified time has elapsed after the motor up-down flag 33 was reset, the zero-crossing counter 41 is reset, and the conducting angle of the TRIAC 22 is slowly reduced, until the value of the zero-crossing counter 41 becomes 10 thereafter. When the value of the zero- crossing counter 41 becomes 11 thereafter, the conducting angle of the TRIAC 22 is set at 0 deg.. |
