| 摘要 |
PURPOSE: A system and a method for reducing the noise of an elevator at midnight are provided to reduce the noise generated at midnight by decreasing the speed of an elevator at night. CONSTITUTION: A system for reducing the noise of an elevator at midnight comprises an operation time deciding unit(2) deciding the night operation time range and daytime operation time range, a central processing unit(1) commanding the order frequency of an elevator drive motor(9) corresponding to the operation time range by dividing the operation speed into acceleration range, high-speed operation range and speed reducing range, a frequency control unit(3) determining the control frequency of the motor according to the order frequency and the operation time deciding signal, a frequency conversion unit(5) converting the frequency to the control frequency determined by the frequency control unit, and motor drive circuits(6,7,8) driving the motor with the frequency decided by the frequency conversion unit.
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