| 摘要 |
PROBLEM TO BE SOLVED: To surely compensate the reduced amount of the number of rotation of a fan motor when a power supply voltage is cut or stopped instantaneously or the voltage is reduced. SOLUTION: The driving controller for the fan motor is provided with a zero cross detecting circuit 22 for detecting the zero cross of the input waveform of a commercial power supply, a reduced voltage detecting circuit 23 for detecting the reduced condition of the commercial power supply and a control table 25a, previously registering the driving control value of the fan motor 31a for compensating the reduced amount of the number of rotation of the fan motor 31a due to an instantaneous interruption of the commercial power supply on an instantaneous stop. When the instantaneous cutting or stopping of the commercial power supply is detected based on the zero cross signal, the control unit 24 searches the control table 25a based on the time of the instantaneous cutting or stopping and controls the driving of the fan motor 31a based on a power-up rate and the number of cycle in accordance with the time. When the reduced condition of the voltage is detected, the driving of the fan motor 31a is controlled by the power-up rate corresponding to the rate of voltage reduction.
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