A line reactor is an impedance device. Its benefits are reduction of drive cross talk, and interference. Input reactors will limit the waveform distortion and harmonic voltages. This will help to improve the power factor due to a reduction of the RMS currents in the system.
Output reactors are generally good up to 100 feet is distance (drive to motor). The benefits are the damping of peak voltage overshoots, which will reduce internal motor heating and lessen the "noise" that a motor can produce when it is run by a drive. On installations where the distance is greater than 100 feet, filters are recommended for motor protection.

Thank you sir.

Thankyou for the above mentioned about choke purpose . I have a doubt about the output reactors i have sound in My VFD used for fan application , maintaining Internal frequency ( PWM frequency setting 4 Khz) u mentione filters can u please inform about that how to improve the efficiency of both motor and drive .

Regards ,

Sk.Raffique,

India