Tractor charging

[Vinpetrol]

Tonight I’m whirlwind sitting (4yearold grandson)
I will check the resistance tomorrow if I can figure out how to do it !
I’m starting to think I should just commit and buy a new alternator . I’m not sure though whether I should buy an original along with a battery temp sensor or a Lucas 17ACR and then wire it up to suit that .
What’s advice ?

 

[V8Druid]

Tonight I’m whirlwind sitting (4yearold grandson)
I will check the resistance tomorrow if I can figure out how to do it !
I’m starting to think I should just commit and buy a new alternator . I’m not sure though whether I should buy an original along with a battery temp sensor or a Lucas 17ACR and then wire it up to suit that .
What’s advice ?

 

[Gecko]

I do have a multimeter but I don’t know how to measure resistance , how’s it done?

No problem. What sort of meter do you have?
You may have an auto-raging meter or many band setting positions. If the two 1/4" spades are common, I'd expect a low resistance (less than 2 Ohms). If it's expecting a temp sensor, I'd expect it to be much higher.
My 3CX has the same Alt. but no temp sensor, so yours may never have had one either.

I’m starting to think I should just commit and buy a new alternator .

Too soon for that.
We've established your current Alt. is wired incorrectly, so a new one (wired the same) won't work either.

try the brown and yellow wire with engine running and using the alternator body for negative the terminal is reading +.5v

Was the meter set to DC?
Try again with the meter set to AC
Some meters have a Hz position too - if you select that, you should see the reading change with revs.

 

[Vinpetrol]

No problem. What sort of meter do you have?
You may have an auto-raging meter or many band setting positions. If the two 1/4" spades are common, I'd expect a low resistance (less than 2 Ohms). If it's expecting a temp sensor, I'd expect it to be much higher.
My 3CX has the same Alt. but no temp sensor, so yours may never have had one either.

Too soon for that.
We've established your current Alt. is wired incorrectly, so a new one (wired the same) won't work either.

Was the meter set to DC?
Try again with the meter set to AC
Some meters have a Hz position too - if you select that, you should see the reading change with revs.

This is the meter

 

[V8Druid]

Bigger the number - greater the resistance Vin

 

[Vinpetrol]

Resistance is -54.3
Swapping the leads around it stayed at 1
What does that tell me ?

 

[V8Druid]

Resistance is -54.3
Swapping the leads around it stayed at 1
What does that tell me ?

assume you have the battery disconnected Vin? plus all connection leads

 

[Vinpetrol]

assume you have the battery disconnected Vin? plus all connection leads

No , battery was connected . Do you mean the alternator leads ?

 

[V8Druid]

No , battery was connected . Do you mean the alternator leads ?

you need to isolate the item that you are testing otherwise you'll get false readings from everything else it's connected to

 

[Vinpetrol]

I disconected everything
Resistance stayed at 1 no change at all

 

[Vinpetrol]

I disconected everything
Resistance stayed at 1 no change at all

What does that mean, are the 2 terminals connected ?

 

[V8Druid]

I disconected everything
Resistance stayed at 1 no change at all

1 what Vin -- what range were you on on the meter

 

[V8Druid]

What does that mean, are the 2 terminals connected ?

1 ohm would indicate that, but would expect to see 0000 ... 1 mega-ohm would indicate major resistance

 

[Gecko]

As above - disconnect the battery (or Alt wires), set the meter to "200 Ω". Then check the meter to see what "zero" looks like by connecting the leads together (should be 0000, but rarely is).

If you get the same reading between the two spade terminals as you do with just the leads shorted, that will tell you your Alt. is not expecting the temp sensor, but has the terminal in case you have the wire floating around.

Things like temp sensors became unnecessary when the regulators got more sophisticated, but replacement Alternators were built to look the same so looms didn't need changing.

 

[Vinpetrol]

Ahh I had it on 200k ! It has the ohms symbol so I put it there . Will have another bash today

 

[Vinpetrol]

Right , I’ve checked the ohms at setting 200
This is the meter when the probes are apart

This is the meter with probes touching

When I checked the resistance across the 2 smaller terminals on the alternator with everything disconnected it read 1 as in the first pic . What does this tell me ? They aren’t connected inside the alternator ?
I then removed a wire that is attached to positive terminal on battery that looks like an addition .
It is connected to another wire with a block connector that heads off in the direction of the alternator .
When I removed it I know longer had 12v at the brown wire .
I managed to check the resistance of both ends of this wire and it read 00.5
Would this mean that the brown wire is connected directly to the battery and should therefore (or could be used as the charging lead)?
Also there is a number on side of alternator regulator , this is it

 

[V8Druid]

sadly you may have cooked your meter trying it with 12v in the circuits - or it might want a battery replacing ..... you should get 0000 on screen with the probes shorted to each other - could also be dirty terminals in your meter's plugs

 

[V8Druid]

Right , I’ve checked the ohms at setting 200
This is the meter when the probes are apart ... 1
This is the meter with probes touching ...... 2
When I checked the resistance across the 2 smaller terminals on the alternator with everything disconnected it read 1 as in the first pic . 3What does this tell me ? They aren’t connected inside the alternator ?
I then removed a wire that is attached to positive terminal on battery that looks like an addition .
It is connected to another wire with a block connector that heads off in the direction of the alternator .
When I removed it I know longer had 12v at the brown wire . 4
I managed to check the resistance of both ends of this wire and it read 00.5 5
Would this mean that the brown wire is connected directly to the battery and should therefore (or could be used as the charging lead)?
Also there is a number on side of alternator regulator , this is it

that's the same reading as open circuit so guessing no continuity -- but as said meter may be suspect???? 1&2&3
alternator heavy brown usually feeds the battery via the main pole on the starter's connection and thence back to the battery - there isn't usually a feed from alternator to battery like that 4
you read the resistance of the length of wire with a probe at each end?? 5

 

[Vinpetrol]

that's the same reading as open circuit so guessing no continuity -- but as said meter may be suspect???? 1&2&3
alternator heavy brown usually feeds the battery via the main pole on the starter's connection and thence back to the battery - there isn't usually a feed from alternator to battery like that 4
you read the resistance of the length of wire with a probe at each end?? 5

I tested the resistance on the brown wire that I think is going to the battery with a probe at each end and the wire disconected from the battery .
I think someone has bodged some wiring on it to get it to charge with a different alternator . Do we know enough to get another alternator and wire it up with what we have to get it charged ?

 

[Gecko]

When I checked the resistance across the 2 smaller terminals on the alternator with everything disconnected it read 1 as in the first pic .

Just checking - the first shot of the display (with the leads open) has the "1" on the far left of the display, but on the second pic, the .4 is on the right side. When you measured the tow spades, was the "1" on the left or right side?

another thought - do you have a spare light bulb lying around you could put the meter on? (headlight, tail light - anything to test the meter).