Strange alternator operation

[abl567]

Recently my alternator light has begun to remain on after starting, not charging at all, then after reaching operating temp it goes out suddenly. I've installed a volt meter now and can confirm it is charging the instant the light goes out. It will sometimes glow very dimly, with no charging, and sometimes glow brightly, again no charging. Once it is out it charges at 13.2-13.5 volts.
Today on start up it went out immediately, charging at 13.5 volts, but came on and stopped charging at the end of my driveway, about 200 yards, then went off and charging normally after warm up.
Any suggestions? Bad earth maybe?

 

[Styria]

Anthony, pull it off and let an Auto Electrician test it for you. Generally speaking, replacement of the regulator will rectify the problem. On the other hand, however, there may be more serious internal issues, involving the stator etc.

I have just passed a 450SE Alternator to my Auto Electrician, but faulty stator windings dictate a more serious approach, such as another unit completely. Regards Styria