1.confirm what is the total capacit of the load. 2. Study the type specifications and main parameters of the Frequency Converter. a. Converter rated voltage: 220V, 380V, 660V, 690V, etc. Converter rated frequency 50hz 60hz or 400hz. b.Converter is the maximum power when the inverter runs, and sometimes the number of converters is increased according to the load and the use environment. c. rated current: the maximum working current when the Converter runs, and the current of the Converter must be greater than the rated current of the motor. d. Converter overload capacity: fan, water pump inverter overload 120%, universal overload 150%;