When the capacity of the inverter is large, it will also distort the voltage in this local power supply line system. The following are summarized here to illustrate the harm to electrical equipment caused by the harmonic interference of the frequency converter due to the excessively long line or the excessive capacity of the frequency converter. (1) The influence of the harmonics output by the frequency converter on the motor

① The generated harmonic current will directly cause additional heating of the motor, causing the motor stator winding to exceed the rated temperature rise of the motor itself, so that the rated output capacity of the motor will be greatly reduced.

②The current waveform output by the inverter is not a complete sine wave, it will increase the peak voltage of the motor, so it directly affects the insulation level of the motor.

③ Harmonics will be a vicious circle, causing additional torque to be generated by the output current component, which will cause a serious drop in the motor output torque.

④ The increase in frequency components of the inverter carrier caused by harmonic interference will directly cause the vibration of the motor core and generate electromagnetic noise. Considering all the above reasons, combined with the factors of safe use of electricity, it is recommended not to use a frequency converter and a motor for long-distance connection control. Its cost is higher than the cost of overhead lines or buried power cables.

If conditions do not permit, for long-distance operation, it is necessary to purchase additional matching "input reactor or input filter" and "output reactor or output filter" according to the rated output power of the inverter. The operation manual of the reactor and the operation manual of the reactor can be connected correctly.