Alternator stripdown pictures

[mp3oplecarrier]

I have a problem with my alternator at the moment as mentioned in another thread, and as I have my previous failed one I thought I would strip them down to try and make a good one.

View of the positive end of the three sets of windings


All three ends of the windings connect into the diode pack


Bottom view of diode pack


Top view of back end


As far as my (limited) understanding goes, as all the windings go into one connection that makes this a single phase alternator which produces AC at the windings which is rectified in the diode pack into DC which is output at the case (-tive) and the large bolt (+ive). The 2 pin connector I believe is for the dashboard ign light and tacho feed.

After stripping both the current and the old alternator I took some measurements:



These were taken on the current not working alternator, impedence on the left and a diode check on the input and output of the diode pack. The resistance seems reasonable for a long run of copper wire, and the diode test seems to show the diode pack doing as it should. When I tried these same measurements on the old alternator I got .2 ohms on each wire, the diode test came out the same.

The question is (are!)

Do I understand correctly how these things work?

Am I taking the right readings?

If neither of these work (they don't) what readings should I get?


Steve

[brorabongo]

Answers to your questions:-

Don't know.

Don't know.

Don't know.



Readings from my old alt (front bearing fault) were:-

.3 ohms for each of the three windings

When diode test done the with the same polarity as the dark blue line I would get a reading, (465) and when I reversed polarity (leads) it shows an open circuit, as expected.

[apole]

Hi,

I don't know either but have found a couple of web sites that may shed some light on it:
http://www.misterfixit.com/alterntr.htm which explains why the 3 windings

If you have the 3 windings with about the same readings could it be the voltage regulator is damaged?

http://autorepair.about.com/cs/electric ... 22700a.htm

At bottom of page one says:
When you first start your car, the alternator needs some current to start working. The voltage regulator supplies this current to the field (stator) terminal of the alternator to get it started

From what I know (which is nothing tbh here !!) but reading up at least you have the 3 windings that seem to be okay, you have tested the diode pack which again seems okay and that leaves the regulator. Dunno how you test that but maybe worth checking.

Also what is the most likely thing to have been damaged by the water? Could you just change that between alternators and see if that helps.

Andy