Nice finds and acquisitions! I don’t know their origin, but may I hazard a guess ?
They could be pre-WW2 German, but Germans had a tendency to proudly label, number, and trademark their motors. Could even be Polish, Czech, or obscure USA “student motors”. That crude but industrial/functional styling is oft used as instructional motors in early to mid 20th century classrooms ; or electrical correspondence schools. When I find one like that , I first test run on low volt DC and simply see if it runs. If not , I try and VOM meter the connections and LIGHTLY clean contacts. I prefer to retain much of the original build parts, windings, and colors as practicable (because that’s the way someone originally built it). Series wound, shunt wound, compound wound can get fascinating.
When I was a kid , brand’s like REMCO and Aristocraft etc from the 1940’s to 1970’s had kits where kids, students, and vocational classes could construct, wind, and run small motors. Welch Scientific and Cenco had a few nicer models. Gilbert even had an early 1900’s kit version of their battery DC motors that could be assembled and of course they showed putting a fan blade on it (the fan could be used to push air and “fly” a tethered paper airplane for impressive effects). Nowadays almost all build-it-yourself educational kits are from PRC China . Once they run, you gotta make it do some kind if work, fan blade shows and feels like its complete.
Comic book ads in the 1950’s had much enticements for kids to power-up and learn electro-motive forces.