Hi,
filters on the output side of the VFD are indeed a different kettle of fish and you should follow manufacturers spec TO THE LETTER or risk
blowing the output IGBTs.

Line reactors are used on the input side, hence the line in line reactor.

The purpose is to improve power factor and decrease the stress on the supply, particularly excessive heating of the wiring
and distribution transformer. If you don't care about what your machine does to the quality of the input supply, or the potential
increased heating of the wiring in your house then don't bother with line reactors.

In New Zealand its covered by:

https://www.worksafe.govt.nz/laws-an...s-of-practice/

And that Code of Practice has legal teeth in the following IEC regulations:

IEC 61000-3-2
IEC 61000-3-3
IEC 61000-3-12

The IEC standards underpin the Harmonic Current limits regulations all around the world.

virtue of choke on the VFD inputs in large industrial plants to improve P.F. and save on power costs as about the only advantage.
The power supply company will insist that you control harmonic currents otherwise they are within their rights to deny to connect you.........that
is a distinct advantage of using reactors.

the input to just about all VFD's is a 3p rectifier and a large capacitor bank, So it virtually absorbs any spikes etc.
It is BECAUSE of the rectifier/capacitor bank that current IS DRAWN in pulses or spikes.

In the attached pics are a simple single phase rectifier and capacitor driving a 20 ohm load. Note that the average output current is about 16A but
particularly in the RectifierCapacitor pic the peak current drawn from the supply is 100A. The same circuit but with a 10mH reactor in-line
reduces the current peak to just over 30A, a marked improvement, but still quite high.

Craig