| 摘要 |
PURPOSE:To realize the stable and highly accurate control of an exhaust fan motor by a constitution wherein a blower is controlled by the result of comparison between the air flow rate flowing in an exhaust duct and the set initial reference value of air flow rate in the titled automatic exhaust fan motor control type system. CONSTITUTION:The initial reference value of inducing air flow rate is selected in accordance with the magnitude of an indicator draft capacity and set at an air flow rate setting circuit 15. In addition, an exhaust fan motor 21 is put into operation and the openings of manual/automatic dampers of scheduled draft chambers are adjusted to the magnitudes of the capacities of the respective chambers. After that, when the number of the draft chambers in operation changes during the operation of the system, a differential calculator 17 compares the detection signal of an air speed sensor 9 with the reference value of an air rate setting circuit 15 in order to increase or decrease the rotational frequency of the motor 21 through an inverter 19. Due to the constitution as mentioned above, the minimum exhaust air flow rate required can be supplied in response to the number of the draft chambers in operation, resulting in obtaining the stable and highly accurate control of the exhaust fan motor.
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