Well dont know much bout dynamos but an alternator needs a permanent live feed to the back. A wire called a feild wire which should go to one leg of a charging bulb then the other leg of the bulb needs to be ignition feed therefore when the alternating is charging it puts a live up the field wire and puts the bulb out. also the alternator will need a permanent earth of the battery on the case, that can just be done through the bracket connected to the engine.
Darren
December 2006