| 摘要 |
PROBLEM TO BE SOLVED: To provide a control method that is used to place a plurality of pumps or fans in parallel operation, and suitable to an inverter system comprising a plurality of inverters performing variable-speed control over motors individually driving the pumps or fans.SOLUTION: An inverter system includes a pressure setter 71, an addition computing element 72, a pressure regulator 73, inverters 13, 23, and 33, and an operation state setter. The inverter 13 among the inverters 13, 23, and 33 is commanded to operate with a value of its reduced output frequency as compared with the inverters 23, 33 by settings of, for example, the operation state setter 81 so as to prolong the lifetime of an electrolytic capacitor for electric power constituting the inverter 13 as compared with the inverters 23, 33. Consequently, the inverter 13 has a longer lifetime than the inverters 23, 33 so as to obtain the effect in avoiding a stop state of the whole inverter system. |
