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Can I run a 3-Phase Alternator with failing Diode Pack in 2-Phase?

My alternator warning light has just started glowing slightly. The Battery voltage at the terminals is at 14.3 - 14.5v (seems steady) but the smaller wire that feeds the waring light is only at approx 13v (all irrespective of load). It is 3 - phase alternator and I believe this fault may indicate a failure of one of the Diodes ?

I need the vehicle to go on holiday for a week starting Wednesday and unfortunately cannot obtain either another alternator or Diode pack before then (the local scrappies don't have them either).

The question... as the batteries appear to be receiving adequate voltage is it going to last for a week's driving or is it going to run flat at some point?

Thank you, Steve

Reply to
SandS
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Is there an auto-electrician anywhere near you? My local chappy will check over, and fix, an alternator within a couple of hours. Cheap too.

Oh, and is it worth risking your holiday for £15 or so?

Si

Reply to
Mungo "one shed" Toadfoot

One of the warning light diodes is open circuit. This doesn't affect alternator output. You should be ok, but with electrics it's never possible to be 100%. In my experience if one diode has packed in, then the rest aren't far behind.

Reply to
John Egan

Thank you for the info John. That sounds exactly like the problem. Fortunately I was able to find a new replacement today at £75 with 1 year guarentee so that wasn't too bad considering the only scappy with one in wanted £35 and a 30day guarentee (its for a Talbot Express van by the way).

The new one does have an extra terminal though which is causing me some concern. It has the 2 normal ones (large one for battery connection and small one for the warning light), but it also has one marked -ve. It doesn't seem to matter if I connect it to ground or not so I've decided to connect it to the alternator body temporarily until I can find out if it needs to be connected or not. Any ideas ?

Thanks again, Steve

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never possible

the rest

slightly.

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Wednesday

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going

Reply to
SandS

-ve is ground. It's connected to the body of the alternator internally via the negative plate of the rectifier.

Reply to
John Egan

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