According to the load characteristics, choose the type of frequency inverter. If the load is constant torque load, please choose the general frequency inverter. If the load is fan, pump load, please choose fan, pump frequency inverter. Because for the fan, the pump load, the torque will increase as the speed increase, but the torque is small when it start up.

When you choose the type of frequency inverter, please select the actual motor current value as the basis, the motor rated power is only for your reference. In addition, please take full consideration of high harmonics from the frequency inverter. The high harmonics will make the motor power factor and efficiency deterioration. So compared with the power grid power supply, the motor current will increase by 10% and up temperature will increase by about 20% when power is supplied to the motor by frequency inverter. Therefore, when you choose motor and frequency inverter, this situation should be took into account and please leave a appropriate margin to prevent rising temperature and affecting the motor life.

When connecting wire between frequency inverter and motor is too long(exceeds 50m), please take measures to suppress the influence of the long cable to the ground coupling capacitor and avoid too small output current and torque. You can choose the bigger power frequency inverter or install the output reactor in the output side of frequency inverter.

For some special applications, such as high ambient temperature, high switching frequency (especially high noise restrictions applications, for example, building automation), high altitude region, where will cause the frequency inverter derating capacity, so you need to choose the higher power frequency inverter.