Tractor charging

[Vinpetrol]

My tractor isn’t charging the battery
The alternator is live from both the black lead and brown lead whether ignition is in on or off position .
The ignition seems to be energising w

 

[V8Druid]

My tractor isn’t charging the battery
The alternator is live from both the black lead and brown lead whether ignition is in on or off position .
The ignition seems to be energising w
View attachment 75271

View attachment 75271

regulator u/s ?
brown / yellow to tacho??

 

[DaveDCB]

Bad earth somewhere?

 

[Thomas7740]

A highways Ford?

 

[Vinpetrol]

My tractor isn’t charging the battery
The alternator is live from both the black lead and brown lead whether ignition is in on or off position .
The ignition seems to be energising w
View attachment 75271

View attachment 75271

I fell asleep while I was writing this up I must of hit the post button when I nodded off
I meant to add that the ignition is energising other poles when you turn it to on position and stops when you turn it off so I think it must be ok but I don’t thinks it can be right that the black lead is live all the time , shouldn’t that be the exciter that’s only live with ignition on and if that’s correct is that pointing at alternator being fecked ?

 

[Vinpetrol]

A highways Ford?

Yes Thomas it’s a 1983 335 pretty much the same as 3910 I’m lead to believe . I put flail on it last weekend and it ran very well so I’m delighted with it other than the charging issue and a rotten cab

 

[Gecko]

I don’t thinks it can be right that the black lead is live all the time

Can you disconnect that black wire and test to see if it's the wire that's always hot or the alternator terminal.

 

[Vinpetrol]

Bad earth somewhere?

The starter has an earth to it so I’m assuming that’s ok

 

[Vinpetrol]

Can you disconnect that black wire and test to see if it's the wire that's always hot or the alternator terminal.

That’s a good shout , will do that this evening and post up result

 

[craig]

Has it got a charging light on the dash and is it working?

 

[Vinpetrol]

Has it got a charging light on the dash and is it working?

Yes it has one , no it’s not working

 

[V8Druid]

Yes it has one , no it’s not working

charge light works by having two live supplies and one is to earth when the alternator isn't charging - when it starts to charge the earth disappears and the bulb goes out as it no longer has an earth - if the lead from the alternator is continuously live my guess is the reg is foobarred (and that's almost certainly why the light ain't working [unless the bulb is bollo-ed] ) reg. can either go open circuit or to earth or total short.

 

[craig]

Yes it has one , no it’s not working

That could be your problem. Some alternators need the bulb to work.
With ign on check for power up to bulb holder, test the bulb, if both ok, pull small black wire and with ign on short it to earth, if it lights, reconnect and put a temporary earth for alternator body to tractor earth, if still not lit its the alternator.
Another test, from the small terminal rig a bulb holder and bulb connected to a positive supply, A older type test lamp with a bulb in will work, and start to see it the bulb goes out, your problem is in the wiring.
With it running try tapping the alternator body with a hammer, if it starts charging brushes could be stuck.

 

[Vinpetrol]

Can you disconnect that black wire and test to see if it's the wire that's always hot or the alternator terminal.

Just tried that , the black wire is live with ignition on or off and once removed from the alternator there is no power at that terminal on the alternator

 

[Steve]

Surely the exciter wire is the brown with yellow trace & red crimp . If you earth it out with the ignition on and the light comes on the alternator is faulty.

 

[craig]

Surely the exciter wire is the brown with yellow trace & red crimp . If you earth it out with the ignition on and the light comes on the alternator is faulty.

The brown and yellow is connected to a `W` terminal, they are usually for tachometer.

 

[craig]

Just tried that , the black wire is live with ignition on or off and once removed from the alternator there is no power at that terminal on the alternator

If the wire is live with ignition on or off, there is either a wiring problem or a problem in the key switch.

 

[Vinpetrol]

If the wire is live with ignition on or off, there is either a wiring problem or a problem in the key switch.

I thought that might be the case Craig but if the alternator has been getting a 12v feed to the exciter then the alternator when it’s running should be charging shouldn’t it ? Could it be a faulty ignition and a faulty alternator ?

 

[Gecko]

If the wire is live with ignition on or off, there is either a wiring problem or a problem in the key switch.

Have to agree - something NQR.

Just a sanity check - the fat brown wire (to B+) is live at all times?

Can you see a part number on the alternator?

The three spade terminals (2x 3/8", 1x1/4") make it look like a Lucas AC or ACR alt (except they are unused).
It looks very much like a Lucas A127

 

[Vinpetrol]

Surely the exciter wire is the brown with yellow trace & red crimp . If you earth it out with the ignition on and the light comes on the alternator is faulty.

The brown and yellow is connected to a `W` terminal, they are usually for tachometer.

The brown and yellow was working as an earth as I used it to check the other wires for 12v current . Does an alternator normally have an earth wire to it ?