On an AC alternator, the generator terminals are the connection point between the main stator windings and the load. Often a plastic terminal board formed with threaded studs embedded into it, cables come from the main stator and are attached to the terminals with spring washers, flat washers and nuts. Plastic is ideal for the terminal board material due to its electrical insulating properties.
Not all AC alternator have terminals. In order to reduce cost in some arrangements manufacturers remove the terminal box which is an enclosure, normally made of steel, but sometimes plastic and the terminal board and instead use a flying lead arrangement to take the power directly from the main terminals to another distribution point (such as an MCCB, bus-bar or other switching device).