Where are the rectifier diodes on a Ducillier Alternator ? It is labelled as a 14V 22/30 Amp model. Just a bit concerned as the main output stud is marked + with a sine wave sign adjacent to it (indicating ac) output.
I have seen a thread that some older alternators had a rectifier under the dash. My 1963 van was 6 volt dynamo, so obviously there isn't anything on my dash.

Hi bobh,
if we're talking about Duc E llier alternators, the diodes are always inside the casing.
That plastic cover clipped onto the back of the alternator has a couple of holes in it because some versions of these alternators had exposed pins which provided unrectified voltage to the 'magic box' that controlled a (lack of) charge warning light.
However, the 'sine wave signs' are present on all of the plastic covers.

If there aren't a couple of brass pins poking out of the alternator, similar to those on an ignition coil, you can breath easy...

ken

Thanks Ken, found them under the cover, and seem to be working when tested with my meter. The alternator is in a bit of a state as both the brush carrier and fuse are cracked, the fuse with fuse wire soldered over previous burnouts. The slip rings are well worn, so I have skimmed these up on the lathe. I wonder what minimum diameters are acceptable? What causes the fuse to blow besides short circuits?
Bob

Bob
a loose connection at the battery?
The alternator doesn't have a 'buffer' then, so current draw can be high enough to pop the fuse(s), if I understand correctly...

Also, an electro-mechanical voltage regulator which has gone 'high' certainly makes the brushes disappear rather quickly, as will either type of VR if it's got a poor earth.
I'd guess that extra wear and tear affects the slip rings as well, but don't know what effect it would have on the alternator fuse plate.

ken