The following points should be determined when selecting the frequency converter:
1. The purpose of using frequency conversion; constant pressure control or constant current control, etc.
2. The type of load of the inverter; such as vane pump or displacement pump, etc. Pay special attention to the performance curve of the load, the performance curve determines the way and method of application.
3. Matching problem of frequency converter and load;
1) Voltage matching; the rated voltage of the inverter matches the rated voltage of the load.
2) Current matching; for ordinary centrifugal pumps, the rated current of the frequency converter is in line with 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.
3) Torque matching; this is possible with constant torque loads or when there is a reduction device.
4) When using an inverter to drive a high speed motor, the increase in high harmonics leads to an increase in output current values due to the small reactance of the high speed motor. Therefore the selection of the inverter used for high-speed motors, its capacity should be slightly larger than the selection of ordinary motors.
5) If the inverter to long cable operation, at this time to take measures to inhibit the impact of long cable to ground coupling capacitance, to avoid the inverter power shortage, so in this case, the inverter capacity to enlarge a gear or in the output of the inverter to install the output reactor.
6) For some special applications, such as high temperature, high altitude, this will cause the inverter to reduce the capacity, inverter capacity to enlarge a gear.
