Posted: Mon Apr 17, 2006 8:46 pm
Check the wiring, make sure there aren't any loose or frayed wires as well as corrosion on anything. If that isn't the case, I'd still say it's the regulator. Usually when an alternator dies, it just dies, it usually won't be sporadic.
The most common things that happen to an alternator (no particular order):
1: Open field-To check that you would put an ohmmeter on the field terminal and the other probe on ground. Of course, for an open field you'd get infinite resistance.
2: Dead short in the field. Same procedure as above, except you'd get no resistance (0 ohm).
3: Stator windings/diodes gone. This results in reduced output, mainly a huge loss of output current (but usually only a slight loss of output voltage). You've got three phases, so you can lose one and get reduced output for a while. The added stress to the alternator will pretty much guarantee the eventual failure of the rest, though.
4: Mechanical failure-Pretty self explanatory. Bearing failures are the most common.
The most common things that happen to an alternator (no particular order):
1: Open field-To check that you would put an ohmmeter on the field terminal and the other probe on ground. Of course, for an open field you'd get infinite resistance.
2: Dead short in the field. Same procedure as above, except you'd get no resistance (0 ohm).
3: Stator windings/diodes gone. This results in reduced output, mainly a huge loss of output current (but usually only a slight loss of output voltage). You've got three phases, so you can lose one and get reduced output for a while. The added stress to the alternator will pretty much guarantee the eventual failure of the rest, though.
4: Mechanical failure-Pretty self explanatory. Bearing failures are the most common.