| 摘要 |
PROBLEM TO BE SOLVED: To select necessary rotation command voltage by providing means for providing several kinds of speed selections by ON/OFF combination of a rotary command switch. SOLUTION: When a rotary switch 8 is turned on, rotation command voltage is outputted from a speed setter 9. By a differential amplifier 10, the rotation command voltage and voltage from a frequency-voltage converter 7 are compared with each other, a rotating speed error is detected, a degree corresponding to the difference is amplified, and speed is controlled by a frequency converter 11. For example, when a pumping quantity of a pump 1 is changed, the pumping quantity is easily changed by changing a value of the rotation command voltage. Since the pumping quantity of the pump 1 is changed by changing the rotation command voltage with ON/OFF combination of the rotation command switch 8 while using two rotation command switches 8, several resistors, and an IC for a selector, it is possible to provide a control device of a circulating a pump having a good usability. |
