The role and difference of input reactor and output reactor for inverter

1. Input reactor

Connected between the power supply and the inverter, it can limit the current impact caused by sudden voltage change of the power grid and overvoltage operation, effectively protect the inverter and improve the power factor of the inverter, and suppress the harmonic current of the inverter input power grid.

Features: reduce the noise of the motor and reduce eddy current loss.

Function:Input reactor reduces input high-order harmonics and used for smooth filtering to reduce transient voltage and extend the life of the motor.

And it can also protect the power switching devices inside the inverter to avoid obvious interference to other equipment.The voltage imbalance between the power supply phases is less than 1.8% of the rated voltage, and the impedance is extremely low (the power transformer is more than 10 times the rated value of the inverter).

2. Output reactor

Mainly used in industrial automation system engineering especially in the case of using inverters to extend the effective transmission distance of the inverter and effectively suppress the instantaneous high voltage generated when the IGBT module of the inverter is switched.

The output reactor installed in the inverter input and output protection circuit is used to reduce the du/dt value at the motor terminal.

The output reactor has many functions , eg.compensate for the influence of the distributed capacitance of the connecting cable between the inverter and the motor ,effectively suppress the harmonics of the inverter output, reduce the noise of the inverter, and avoid premature aging of the motor insulation or early damage to the motor.

When the inverter and the motor are connected by a long cable, the output reactor can reduce the peak value of the load current. However, the output reactor set at the output end of the inverter cannot be used to reduce the peak value of the transient voltage on the motor.