NONE of the wires in the three-wire harness should go to ground. If they do, the stator windings are burnt, and shorting to ground. Have you done this yet???
That test is simply to confirm/eliminate a burnt stator. Nothing else. If it is NOT burnt, there is more testing you can do.
If it is burnt, it will be difficult to determine what caused it, and it would be prudent to replace not only the stator, but also the regulator/rectifier and battery. If you just replace the stator, and re-install a crook reg/rec, you'll burn the new stator too.
A bad reg/rec, or even a bad battery, can continuously draw maximum output from the alternator, and fry all three components - stator, reg/rec, and battery.