Taking alternators

[Currymunster]

Hi all,
Before I start hello every one.
I'm question is the A127i-100 alternator from a land rover Discovery 1
Slip ring bearing went and stopped charging. Head a spare so thew that on and shelves it with the intention of fixing it.
Two years later the spare one starts charging for maybe 3 miles and then the rev counter fails till it's cool again.
So I'm ordered a kit for the first one.
Front and rear bearing, slip ring, diode pack and regulator. Fit it all and hey battery light on permanently. Would slightly fade at high revs but no charge whatsoever! Wtf
So I swap the parts to the one on the car.
All works just fine.
Now on the bench the stator and rotor tested the same but I know one is faulty.
Both measured 2.8ohms on the slip ring with continuity to the spindle.
Stator confuses me as it has six wires and not 3?
Continuity shows three pairs but again no continuity to the case
Wye or Delta?
Anyone know what I'm missing.
It's really bugging me.
Many thanks
James

 

[EricMark]

Rotor easy to check, power up and see if rotor is magnetised, never really had a problem, if winding not down to earth and showing continuity then OK, stator much harder to check, and also most likely to be damaged by faulty bearing, as to wiring, originally delta, however Bosch found if wired star and the star point also rectified they could squeeze more out of the same size alternator without over heating.

There are also some single phase alternators, two windings both half wave rectified.

But likely with bearing failure the stator is US.

 

[Currymunster]

Rotor easy to check, power up and see if rotor is magnetised, never really had a problem, if winding not down to earth and showing continuity then OK, stator much harder to check, and also most likely to be damaged by faulty bearing, as to wiring, originally delta, however Bosch found if wired star and the star point also rectified they could squeeze more out of the same size alternator without over heating.

There are also some single phase alternators, two windings both half wave rectified.

But likely with bearing failure the stator is US.

Hi, many thanks for your help.
I finally got round to looking at it again.
I worked out the slip ring was faulty.
When drifting it on it had broken.
I don't quite know what it was doing but when testing with a metre I could see a fault.
However when in use it just blew the fuse or just didn't charge??
New one fitted and now it's as good as new.
Off course, I may have done something else wrong that when taken apart and put back together I didn't do this time. Either way is all working now.
Many thanks.