I got hold of two electrical panels with a bad wiring job and the worst documentation. Not to say that it is completely out of code (racing fast for illegal). The did however turn out to contain a gem of lost times.
A “Speed Commander”, which is a Danish designed and produced 4 kW motor drive. It has a very simplistic interface consisting of only 16 settings. The manufacturer still exists ( https://speed-tech.dk/ ) but does not seem like they are selling motor drives anymore. There is a only a trace after it in the manuals section with refences to a V4 and V5. This is most likely the version 4.
Discussion of the teardown: https://highvoltageforum.net/index.php?topic=1506.0