You can do a basic test. Lay the dynamo on your bench/top of vice. Wind the D&F wires together and connect them to the positive side of a 6V battery. Now earth the dynamo body to the Neg side of battery. The dynamo should motor in the same direction as the drive arrow. Ron
Not usually unless it is a very heavy duty battery charger
However connected to a battery, even a bad one should work.
Or you can use a 12 V battery with a heavy load like a pair of headlamp globes ins series
Ron