When selecting the inverter, the following points should be determined:
1) the purpose of frequency conversion; Constant voltage control or constant current control, etc.
2) Load type of the inverter; Such as vane pumps or positive displacement pumps, etc., pay special attention to the performance curve of the load, and the performance curve determines the way and method of application.
3) The matching problem of the frequency converter and the load;
I. Voltage matching; the rated voltage of the inverter is consistent with the rated voltage of the load.
II. Current matching; For ordinary centrifugal pumps, the rated current of the inverter corresponds to the rated current of the motor. For special loads, such as deep-water pumps, it is necessary to refer to the motor performance parameters to determine the inverter current and overload capacity with the maximum current.
III. Torque matching; this situation may occur when there is a constant torque load or a reduction device.
4) When using the frequency converter to drive the high-speed motor, the output current value increases due to the small reactance of the high-speed motor and the increase of the high-order harmonics. Therefore, the selection of frequency converters for high-speed motors has a slightly larger capacity than the selection of ordinary motors.
5) If the inverter is to run a long cable, measures should be taken to suppress the influence of the long cable on the ground coupling capacitor to avoid insufficient output of the inverter, so in this case, the inverter capacity should be enlarged by one gear or an output reactor should be installed at the output end of the inverter.
6) For some special applications, such as high temperature and high altitude, this time will cause the capacity of the inverter to degrade, and the capacity of the inverter should be enlarged by one gear.