| 摘要 |
PURPOSE:To prevent the overload or the like of an AC motor and to enhance the reliability of the motor by combining the motor operated at a constant speed and an AC motor controlled at its rotating speed, thereby controlling the quantity of fluid. CONSTITUTION:A flow rate reference 71 and a flow rate signal from flowmeter 6 are compared and controlled by a flow rate regulator 7, the output frequencies of variable frequency controllers 31, 32 are varied to control the rotating speeds AC motors 13, 14 and hence pumps 23, 24, therby controlling the flow rate of the fluid. The flow rate is then detected by the input current detectors 911, 912 of the respective motors 11, 12 operated at constant speed, the rated input current value is compared by input electric quantity monitors 921, 922 with the detections signals of the input current detectors 911, 912, thereby controlling so that the output signal does not exceed the rated input current value. |
