| 摘要 |
PURPOSE:To suppress the unnatural feeling of a person blown, by controlling a fan motor in such a manner that a frequency of appearance of high rotational speed of the fan motor is generally less than that of low rotational speed of the fan motor. CONSTITUTION:A rotational speed selecting circuit 2 operates to set three kinds of rotational speeds (high, medium and low) of a motor 1 for rotating a fan, in receipt of a signal from a rotational speed control circuit 3. The rotational speed control circuit 3 counts signals from a reference time forming circuit 4 and maintains a certain rotational speed of the motor 1 for a given time, then sequentially shifting the rotational speed to another rotational speed. The continuation times of the three kinds of rotational speeds are suitably set to form a blowing pattern such that as the rotational speed decreases, a frequency of appearance of the decreased rotational speed is increased. Accordingly, as the rotational speed is shifted from high to low condition, the frequency of appearance of the low condition becomes more. Further, random blowing is associated with the above control. Therefore, it is possible to obtain a blowing condition approximate to a natural wind.
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