| 摘要 |
PURPOSE:To permit multiple stage control of an amount of blowing air with a reduced number of switches, by controlling the amount of blowing air according to deviation between a manual set value of a rotational speed of a blower and a predetermined value corresponding to a maximum rotational speed or a minimum rotational speed of the blower. CONSTITUTION:There is provided a blowing air amount control switch 8 constituted of a blowing air amount decreasing switch 8a and a blowing air amount increasing switch 8b. The control switch 8 is pushed to select a manual control of a blower 3 from an automatic control. Under the manual control, a set value DELTAW is provided by dividing difference between a signal voltage Wmax corresponding to a maximum rotational speed of the blower 3 and a signal voltage Wmin corresponding to a minimum rotational speed by a selection stage number N' of the blowing air amount, thereby increasing and decreasing a signal voltage by the set value DELTAW every pushing number N of the switch 8. The blowing air amount of the blower 3 is controlled according to deviation between the signal voltage increased or decreased as above and an operating voltage of the blower 3. |
