HELP - Autosparks - Diode testing on Alternator Rectifier ??

[bilabonic]

Hi All

Got an old Combo Van with no output from alternator.

Stripped it down and check rotor/fields and all OK. Desoldered rectifier from field and it has 6 diodes, put a fluke on them set to diode and have open circuit one way and .541 to .546 (with quick BEEP) the opposing way, presuming that reading is volts.

I am 'presuming' this means the unit is ok ??

Anyone confirm or advise ???

Cheers

 

[Knobhead]

Considering the rectifier isn’t connected to the field and diode tests read in ohms not volts we could just struggle here. The rectifier is connected to the 3ph stator.
How have you tested the stator and rotor windings, bearing in mind the stator is star connected?
BTW there are 12 tests to check the rectifier

 

[bilabonic]

Sorry my terminology is wrong Tony, rectifier was connected to stator and it was star connected, it was balanced and not to earth.

I presumed when set to diode test the meter outputs set voltage (or current) and gives a set value that the diode has opened (between 0.5-0.8v). It does not state ohms at all on my meter on diode setting ??

Cheers

 

[Knobhead]

Hmm eeerr yes, just looked at my new meter, it is volts. I’ve always used the ohms range for the past 40 years, never used the diode setting. Mind you I’d be trying to punch 1000V through them in reverse.

So the stator sounds OK, I take it the field (rotor) is the same?
I’ll do a drawing for you of the diode pack and show the tests. It will take a little time to do.
I know this is a bit late, the brushes are OK aren’t they? They are the usual culprit, worn out, jambed or shorted.