| 摘要 |
PURPOSE:To minimize the input of a motor with reference to various loads and to maximize the efficiency of the device wherein the output of a minimum input operation device is input and the motor is driven by its terminal voltage and frequency. CONSTITUTION:When an apparatus is connected to a three-phase induction motor 18 to which a load has been connected, the pressure drop signal of a pressure sensor 22 is input to a minimum output operation device 26 when the discharge amount of a pump 20 as a load for the motor 18 is increased, a corresponding frequency (f) is output to a conversion device 12, the number of revolutions of the motor 18 is increased and a drop in a discharge pressure is supplemented. Then, an increase in a rotational speed is input to the minimum input operation device 26 as the output of an operation device 16 or a detector 8, and it is checked whether set values of a terminal voltage V and the frequency (f) which minimize the input are preserved or not. When they are not preserved, a setting operation is performed, a set value is output to the exchange device, and data is preserved. When the discharge pressure of the pump 20 is increased, a reverse operation is performed, and the motor is always operated in a minimum input state. |
