| 摘要 |
PURPOSE:To minimize downtime due to transient abnormality by performing automatic restart control of inverter, through which the characteristics of the cause of abnormality is also decided, upon failure of the inverter performing variable speed control of an AC motor for driving a water supply pump. CONSTITUTION:If an inverter 1 stops due to some abnormal cause during normal operation and an abnormality signal SF1 is outputted, an analog timer ATD is actuated to produce an output pulse for operating a one-shot pulse circuit ISPG1 which then produces an output for setting a flip-flop element FF1 thus storing occurrence of initial failure. Output pulses from the ATD are also fed to NAND2, NAND3 and the inverter 1 is restarted based on an output from the NAND3. If the speed of AC motor increases upto a predetermined level at that time, a decision is made that the inverter 1 has stopped due to some transient cause and thereby operation of the inverter 1 is continued, otherwise power supply for the AC motor is switched through a switching circuit 2 to a commercial power supply. |
