It could be an electric motor. The motor has what would be termed in Italian presa di forza motrice that is something to "take" the force generated by the engine to transmit it elsewhere.

Imagine an external device, such as a small conveyor belt, a small mill, etc. that needs an external force, which is provided by belts which connect both the engine and the tool. In that case, there should be a "tensioner" to keep the belt in tension so that it transmit force to the tool. The cylinders that "spin" move the belt. So it should be an electric engine for some external utilising machine.

If this had to be utilised in a darkroom, it could have been used as part of a rotary processor. The belt would transmit the motion to the tank. Or maybe some kind of contraption would have the tank rotated while being on the same axis of the presa di forza, just as it happens with a Jobo.