1999 S-80 T6 Freewheeling alternator

[SimLyons]

I don't know if this is a problem or a blessing. While searching for an elusive vacuum leak I noticed my alternator wasn't rotating. The engine was at idle and I saw the pulley spinning nicely while the alternator windings where completely stationary. I have no light showing a charging issue. I turned everything electrical on and still no rotation. Would this alternator be a free-wheeling part?

Thanks for any help/advice.

Sim

[JDS60R]

You are probably seeing the stationary winding as the alternator core must turn to create a charge.
The freewheel pulley on the front (if equipped) acts almost like a ratchet so the pulses are not transmitted to the belt. It is never actually freewheeling for more than a few degrees.

[SimLyons]

Thanks for that info! I just got back from 40 mile quick trip and since there were no electrical problems I came to the same conclusion.