Looks to me like they are MG (motor generator) sets...
I am guessing they are being used to generate DC power from AC mains to power electric trollies, elevator equipment,
crane(s)and the like. Scary looking with all those wires just hanging around but a very interesting picture no doubt!
A.D
Are the units actually in service in this picture, or are we just looking at them being tested after manufacture?
beats me. I just like old pictures, and if there are wires in it, all the better
TW
It's hard to tell if that is a temporary setup, or a sloppy installation. Either way, a neat photo in am old mill-type building.