I have got replacement alternator but the wiring positions are different, any ideas of what each is for? It is a Mitsubishi 50A for a Thornycroft T95 engine.
It has similar terminals as the Hitachi(Yanmar) alternators, and the "LR" on the label indicates to me that the 2 blade terminals at right angles to each other are the L and R, ie L=ignition light feed, and R=field wire, from an internal regulator
The big terminal is B+ (batt), and the single blade would then be the earth (unless it is case-earthed, then it may be a tacho feed)