What does this green wire from the alternator do?

I've got a 1977 kz650b. Can't seem to find anything on this green wire coming from my alternator. The three yellow wires are fine and still in the connector but the green wire was cut short. Can anyone tell me what that is?

There should be an answer here....
It appears from the description that begins on page 194, that the green wire comes from the voltage regulator in order to regulate the power going into the electrical system at any given moment.

www.kzrider.com/modules/ServiceManuals/K...Service%20Manual.pdf

KZ650.info wiring diagrams




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Your charging system uses an alternator with a field coil. The field coil generates a magnetic field which varies in order to control the stator's output. The regulator controls the current in the field coil through the green wire. In other words, the green wire powers the field coil, and the regulator controls the green wire. The 1977 model is the only kz 650 using that setup, although other kz's use it, like the 400.

The field coil is grounded through the engine on th 650, while the 400 has a ground wire for the field coil.