Ford 4000 3cyl Generator / Regulator Problem Help!

[kaiserjonty]

Hi there, have just replaced the entire wiring harness on the tractor after a short caused a burn out up near the regulator, the burnt wire was at the 'D' terminal. The tractor had not been running for approx 3 months and so the battery was removed and charged, the Field wire was flashed to the B terminal on the regulator. Tractor started first go and sat at idle for approx 10 mins, shortly after increasing revs there was blue smoke!

The original harness was in very poor condition so a new harness was ordered. New harness has been put on however once the battery was connected I could smell heat, the generator is heating up it is red hot within 5 mins. What could be causing this? What have I done wrong?

I am very much a novice and tried to fault find by doing the following;
1. Battery voltage = 12.52V
2. Checked D wire voltage out from regulator = 12.51 V
3. Checked Field wire voltage out from regulator = 12.51V
4. Jumper wire from battery to Field terminal on generator used volt meter to test D terminal on generator = 27.5 (tractor running)

Is my regulator cooked, did I kill it when I flashed the field to B after I charged the battery?
Are there any other tests I can do to try to determine where the fault is?

Thanks in advance,
Rachel

[essexpete]

Sorry to sound thick, I am not an electrical person but is the gen hot when just connecting battery or when the engine is running?

[kaiserjonty]

Hi essexpete the gen gets hot only when connected via the field and D wires back to the regulator. If I run the tractor without the wires connected it does not get hot at all.

[essexpete]

Could it be possible that the polarity has been upset. Some on here might know.

[kaiserjonty]

With my limited knowledge thats what my head was telling me as well!

[hair bear]

Look at the old harness, the battery terminals should be marked + or -. Check which was the earth lead and compare with the new harness. Pos earth systems were falling out of favour around the time of the 4000 and the new harness may be for a earlier/later machine and as such be the wrong way round.
If that checks out ok, try removing the fan belt, then connect the battery. If the dynamo spins up then there is an almost definite regulator fault. There is a test routine here... https://www.anglo-agriparts.com/testing ... -regulator
Good luck, Rob.

[hair bear]

Should have added...
The starter will self-field so will turn the right way regardless of the polarity.
If the original short circuit cooked the regulator the internal contacts may have welded together and be back feeding the dynamo - hence it acts as a motor, and is trying to turn the engine via the belt. Changing an older machine from + to - earth isn't difficult, and will 'future proof' it in so much that it will be able to use modern trailer boards with led lighting, and with an accessory socket charge a phone etc.! You could also loose the dynamo and control box and convert to an alternator.

[kaiserjonty]

Hi hairbear thanks for your reply. I have attached a couple of photos of the old harness for you, it is a huge mess, as well as the original connection to the starter. Is that what you mean when you say check the battery terminals? The battery positive goes to the starter motor and the negative battery to ground. That is how I have rewired it with the new harness. Cheers

[kaiserjonty]

[hair bear]

Ok, so we're happy that it's correct at neg earth.
It would appear the starter has been replaced at some point, the correct one would have the solenoid on top - don't worry about it, it fits and works, just an observation.
Something to try, remove the fan belt, disconnect the dynamo from the loom. Connect the dynamo terminals together then run a connection back to the pos battery terminal. The dynamo should spin, and it should also correct the field for neg earth. A spinning dynamo shows it's basically good.
With the fan belt off, re-connect the dynamo and battery, turn the ignition on and see if the dynamo spins up, if so. You're almost certainly looking at the regulator box.