@th Woah! where did you find that?...
I'm aware of 400Hz on things like ships / aviation, but 15Hz?! ... I'm guessing rail from your other recent posts?
@th ... I also wonder how you select voltage/frequency and waveform... is it just random / could it change at any time? 😱
@th @attie Apparently https://en.wikipedia.org/wiki/15_kV_AC_railway_electrification 50/ 16.2/35Hz/16.7 is common in Germany; (50/3) - but wth is this thing based on 60Hz and 60/4 ?