Basic alternator wiring

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Joined: Sun Jun 02, 2019 11:01 am
Location: SW France

Basic alternator wiring

Post by stiv » Fri Jan 24, 2020 12:47 pm

I can't seem to get my head around this relatively easy problem. I may be wirelexic...

On my Deutz D 6006, vintage 1969
Deutz D 6006-600x337.JPG
Deutz D 6006-600x337.JPG (98 KiB) Viewed 1429 times
the old dynamo was not working, and when I opened it up I found it to be filthy. Oil or grease, or something horribly black, had coated everything, and the cloth wrapping around the copper windings (?) was rotten. I gave up any hope of restoring it when I clumsily dropped it, breaking the cast iron lugs off.
Deutz broken dynamo-600x337.JPG
Deutz broken dynamo-600x337.JPG (74.39 KiB) Viewed 1429 times
I haven't thrown it away, as there is always a chance that I can find bit in a scrap yard, but...

At the end of last year, just before I broke the engine, I bought a Mahle 65 amp alternator which arrived with no fitting instructions. I fitted it, adapting the bolts, and wired it up by following some instructions that I found on the internet, and which I can no longer find.

I made up a wire, which I connected to the key ignition (there is a pull switch after turning the key to 1st position) and to the alternator D+ connector, and another, thick wire, which I connected to the alternator B+ and either directly to the battery positive or to the solenoid positive, (I can't remember which) same connector as the main battery + wire. I think I also connected the original small wire (the loom still being on the tractor after I disconnected the old dynamo regulator box) that went to the small solenoid connector.
Deutz solenoid-600x337.JPG
Deutz solenoid-600x337.JPG (74.3 KiB) Viewed 1429 times
Since splitting the tractor to repair the engine, the old loom is just a bundle of spaghetti, which I haven't had time to sort out yet. The dash lights etc. are all rusted or broken and don't work, as are the indicators etc., and will need redoing at some time.

I was extremely pleased to be able to start the tractor on the key for the first time since I had bought it 15 years before (yes, I know, but I'm doing it now...). I had, as had the bloke I bought it from, always parked it on a slope and bump started it. The next morning, however, the battery had been totally drained, my voltmeter read only 2 volts... Dead! I did a few basic tests and wondered if the key switch was faulty as I seemed to get a reading even when the key was off.
Deutz key switch, wired-600x337.JPG
Deutz key switch, wired-600x337.JPG (72.36 KiB) Viewed 1429 times
I doubted my wiring too, as I may have connected it the wrong way round or something and so just disconnected everything and parked it back on the slope. Shortly after that the engine broke and it's only recently that I brought the tractor back from the neighbours farm where I repaired the engine in his barn.

I've since learned to start it by shorting across the solenoid with a screwdriver (not, I'm sure, a good practice, but at least I can park near the house!).

My question (if your still with me!) is how should I connect the alternator to be able to start on the key (pull start) and recharge the battery? This assuming that the key switch may or may not be faulty, of course...

The alternator has:
B at 12 o'clock (unless B is the black plastic connector on the yellow wire...)
D+ at 2 o'clock
B+ at 3 o'clock
and a W blade connector under the white plastic cover.
I believe that the W is for an electric tachometer or rev counter, which I don't have (it's a cable).
Deutz Mahle 65amp alternator-600x337.JPG
Deutz Mahle 65amp alternator-600x337.JPG (81.17 KiB) Viewed 1429 times

Thanking you, O wise ones, in advance, for any ideas that you may have,

I remain your bumbling, err... humble servant...

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