It seems that real difference can be measured only when filter is added on the AC input, i.e. before filters built in Mean well LRS converters. More measurements follows.
Measurement #7: AUX-PS module with two Mean Well IRM converters, with MCU module connected, with 2 x Mean Well LRS, added filter on the AC input (Xin=330n,
2x5 mH, Xout=100n, Yout=2x4n7), DCP405 without load connected:
Measurement #8: same as above but with DCP405, Iout=max (5 A):
![](https://i.imgur.com/8YYMWQu.png)
I currently only have a common mode filter with twice the inductance at hand and with it the situation looks better.
Measurement #9: AUX-PS module with two Mean Well IRM converters, with MCU module connected, with 2 x Mean Well LRS connected, added filter on the AC input (
2x10 mH, Xout=100n, Yout=2x2n2), DCP405 without load connected:
Measurement #10: same as above but with DCP405, Iout=max (5 A):
![](https://i.imgur.com/4Luq2kz.png)
I plan to get and test a few more common mode filters with an inductance of 15 to 20 mH before going to the lab. I believe that should help.