Disconnected alternators don't burn up, it is a misconception. What happens is that the open circuit voltage shoots sky high with no load and no current
to keep it down. There is no power being generated, it just blows the diodes by exceeding their maximum reverse voltage rating.
In order to burn the stator, you need to run a heavy current
through, i.e. attach a load. If you short the output, it will slow it right down and drastically reduce the amount of power it is able to produce - that is the underlying logic. However, if the wind gets high enough, then it could burn out. It is a question of whether it can get there or not.
If you open-circuit it, it will cool down, because it is not producing power, but the voltage will get extremely high. It needs to be able to withstand it. The insulation
could fail arguably, even though I have never seen it happen myself.
is largely produced by the current, it is the windings resistance multiplied by the square of the current. No current, no heating