Tom W
Active Member
I decided to give my alternator a mild refresh as I’d experienced some intermittent charging in the past. I found when I stripped it down to investigate, that the brushes and slip rings were slightly worn, so I ordered some spares and decided to rebuild.
The original brushes looked identical to each other. The replacements (NOS genuine Lucas with a red label) have one tag with a terminal on it. I fitted this brush closer to the regulator, as the other has the corner chamfered off, which matches the brush carrier moulding. Does anyone know what this terminal is for? I thought it might be something to do with the battery voltage sensing wire, but it doesn’t line up with the hole for that. My cars never had the sensing wire connected, as the alternator fitted is internally sensed. There’s also a surge protection device mentioned in the manual that isn’t in my alternator. Confusing!
Anyway, the ammeter is showing a healthy charge after the rebuild, so that’s all good. It would be nice to get the battery sensing circuit to work properly though. Partly so there’s something to connect the sensing wire too, rather than leaving it taped up, and mostly because I think sensing the battery directly is better on a system where the battery is in the boot, and could experience a voltage drop.
The original brushes looked identical to each other. The replacements (NOS genuine Lucas with a red label) have one tag with a terminal on it. I fitted this brush closer to the regulator, as the other has the corner chamfered off, which matches the brush carrier moulding. Does anyone know what this terminal is for? I thought it might be something to do with the battery voltage sensing wire, but it doesn’t line up with the hole for that. My cars never had the sensing wire connected, as the alternator fitted is internally sensed. There’s also a surge protection device mentioned in the manual that isn’t in my alternator. Confusing!
Anyway, the ammeter is showing a healthy charge after the rebuild, so that’s all good. It would be nice to get the battery sensing circuit to work properly though. Partly so there’s something to connect the sensing wire too, rather than leaving it taped up, and mostly because I think sensing the battery directly is better on a system where the battery is in the boot, and could experience a voltage drop.