Tractor charging

[Vinpetrol]

Have to agree - something NQR.

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

Yes the fat brown and the black are permanently live wether ignition is on or off

 

[Gecko]

Does an alternator normally have an earth wire to it ?

No. Just grounds through the mounts bolted to the block.

 

[Vinpetrol]

No. Just grounds through the mounts bolted to the block.

So the brown wire with yellow stripe shouldn’t be an earth at all ?

 

[Steve]

So the brown wire with yellow stripe shouldn’t be an earth at all ?

I still think it is the exciter wire. It will read as negative until it has been excited and voltage exceeds the battery which makes the light on the dash go out and triggers the tach to start clocking hours. As said above the warning light in the dash needs to be working to trigger it to start charging unless you trigger it manually.

 

[Vinpetrol]

I still think it is the exciter wire. It will read as negative until it has been excited and voltage exceeds the battery which makes the light on the dash go out and triggers the tach to start clocking hours. As said above the warning light in the dash needs to be working to trigger it to start charging unless you trigger it manually.

As far as the wiring is concerned will ignition on be the same state as engine running ? Should the brown and yellow wire give 12v feed with just ignition on and engine running ? I’m asking as I haven’t checked it with engine running I’ve assumed gnition on is the same state ?

 

[V8Druid]

As far as the wiring is concerned will ignition on be the same state as engine running ? Should the brown and yellow wire give 12v feed with just ignition on and engine running ? I’m asking as I haven’t checked it with engine running I’ve assumed gnition on is the same state ?

nope - alternator is not running/producing charge

 

[Steve]

If you remove the brown & yellow wire, with ignition on and engine off and positive probe on multimeter to that wire, then negative probe to the alternator terminal you should get 12v .

 

[Gecko]

Should the brown and yellow wire give 12v feed with just ignition on and engine running ?

The "W" terminal should have nothing on it when the engine is stopped.
With the engine running, it should have AC with a Rev dependent frequency (to provide something for the Tacho to work with)

 

[Vinpetrol]

The "W" terminal should have nothing on it when the engine is stopped.
With the engine running, it should have AC with a Rev dependent frequency (to provide something for the Tacho to work with)

I think the clock works with just ignition on . I noticed it ticking with ignition on when I was looking at back of switch, the rpm is a drive from transmission

 

[V8Druid]

I think the clock works with just ignition on . I noticed it ticking with ignition on when I was looking at back of switch, the rpm is a drive from transmission

it will

 

[CPS]

Does the charging light come on? Or is the bulb blown?

 

[Vinpetrol]

Does the charging light come on? Or is the bulb blown?

Will check tonight

 

[Gecko]

I think the clock works with just ignition on . I noticed it ticking with ignition on when I was looking at back of switch, the rpm is a drive from transmission

For the hour meter, yes indeed. (don't know why it's usually done like that - if it were wired to the oil pressure switch, the clock would only count 'engine running hours", not 'ignition on' hours)

If the tacho is a mechanical drive, then I'm having trouble guessing what's on the W terminal.

 

[Steve]

Thinking about it the rev counter & the hour meter are mechanicaly driven on the older fords. If the ignition light doesn’t work it could also be corrosion around the bulb holder.

 

[Vinpetrol]

In late from work tonight so didn’t have time to get in about the dash to check out charge lights but did
try the brown and yellow wire with engine running and using the alternator body for negative the terminal is reading +.5v

 

[Vinpetrol]

 

[Vinpetrol]

I found that wiring diagram online (hopefully it’s the right one) . The alt light I put a pencil ring around .
Does this shed any light ?

 

[craig]

Has it charged in you ownership?
The alternator fitted doesn't look original or a like for like replacement.
A brown/yellow wire is normally for the warning light, but on this its connected to what looks like it say W, which are normally for rev counters (w=waveform)
And as far as I can tell your wiring diagram (it a bit fuzzy) has no black wire on it.

 

[V8Druid]

View attachment 75352

certainly looks like the brown/yellow goes to the alternator - via a diode --- what the hell is a battery temp switch???

 

[Gecko]

I wouldn't trust that diagram - if you follow the starter motor high current line, it shows the full start current going through the ignition switch and then a fuse

I've found a diagram for a 455 that might be closer (and it shows the A127 as the original Alt)