This is an axial fan from the famous Italian factory Ercole Marelli. It is a Type ASM 254 and I installed it today in my attic to suck up the cool air from the airconditioned room below. Despite temperatures of close to 40°C up there I tried to match the expectations vintage addicts as myself have in such situations. I used NOS bTicino equipment from the Serie Sporgente Monoblocco in Alberite Superdielettrica (from around 1960 but available for decades). The wiring is new and double insulated to match norms. The plug is old.
REmark The fan is not complete. It had originally a hood that allowed to close it by a loop of cable with had a switch for on/off. I have a NOS complete one and I think about installing it one day in a window. The triple glazing is a challenge. So this adventure is postponed to a later date.