Alternator wiring

[Andy Craig]

Hi Huib,

Thats a good point about the spade connectors riding up inside the plug. I will check that in a few minutes.

Thanks very much for the pics of the alternators - thats a great help. Ours is similar to the one on the left but the male 3-pin connector has been removed. Beneath where that should be, on the right hand side is what i can best describe as a fork-shaped clip. This clip looks like it makes contact with the 3-pin connector by 'springing' up underneath it. To me this looks incomplete and the unit doesn't appear to have either the capacitor or a regulator.

I've just been for a further look and have found the female side of the 3-pin connector on the main harness - it had been cable-tied out of the way for some reason...

The spade connectors did indeed ride up inside the L-shaped plug but still appeared to be making sufficient contact. I'll check they're contacting fully next time i run it, but i guess i'll need to find some parts first?!?

Thanks again,
Andy

[P. de R. Leclercq]

Thanks Peter,

That would be interesting.

Certainly the Fulvia alternators had a seperate Ex wire...

Paul

[P. de R. Leclercq]

OK, but in that case, why the green wire and the Ex terminal?

Paul

[Huib]

For an alternator to do its job it needs:
1) to turn
2) field current
If either one is not there, it won't work.
When the engine is started the alternator faces a mexican stand off. It needs field current to generate a voltage but it cannot get its own field current beacuse it is not generating any voltage

The initial field current has to come from the battery through a resistor to limit the current. If one uses a small lamp instead of the resistor one kills two birds with one stone: a low cost, high power resistor and an indicator to check if the alternator is working.

Once the alternator is working the field current comes from the regulator. Proof that the current no longer comes from the battery through the lamp is the fact that the lamp is not burning.

[Peter Cripps]

Paul and others,

Huib has already covered this, but here are 3 pages from the Bosch Automotive Handbook that describe how alternators work:

http://www.petercripps.com/Lancia/Alter ... nator1.jpg
http://www.petercripps.com/Lancia/Alter ... nator2.jpg
http://www.petercripps.com/Lancia/Alter ... nator3.jpg

(Not sure how to make these links active, so you may have to cut and paste.)

Peter

[shaun pond]

Peter, thank you!

I'd been following this thread with more interest than comprehension.

The Bosch stuff helps a great deal.

Regards

[Huib]

Yes. You need either the plastic part with the 3 pin conector so you can connect the external regulator which is behind the head lamps or a part which has the built in electronic regulator. The plastic part also holds the two brushes.

Note that in many S2 Fulvia's the black wire of the three going to the external regulator also makes the ground connection to the body.

[Andy Craig]

Hi Huib,

I've just been for another look and you're correct : there is a black wire coming from the female 3-pin connector and going to earth. The earth looks good. The regulator is indeed behind the headlight and doesn't look too pretty - the connectors on it look fairly corroded, although they are all still there.

First of all i'll try to find a capacitor and male 3-pin plug locally. I suppose that if i get these parts fitted and there are still no signs of life from the system i'll need to find a replacement regulator?

Andy

[Neil]

Andy, I assume you are based in the UK, I have used a local electrical distributor in Guildford who rebuilt and tested my Fulvia alternator and separate regulator, who I am sure could assist you, mine was a Duceiller unit, but they are Bosch agent. Let me know if you would like their details.

[P. de R. Leclercq]

Thank you Peter, fascinating reading.

I have now worked out of course the function of the Ex terminal. It is via this terminal that the refulator does its work: it measures the voltage output and regulates the excitation current and therefore the output voltage accordingly.

Paul