TEA20 Electrical dramas

pcp20us

Member
Hi all

Ok I have a 12volt -ve earth tractor, It has a 12v generator and starter motor, both are lucas, so assume its a 12v setup not a conversion . I have checked all the cabling and i did have to fix the regulator ( which i still need to test.) I used a wiring diagram from YT for checking the cabling.

However when i flick the switch (ign on) it seems the coil is dragging the voltage down, you can see the meter slowly discharge from 12.6 volts down to about 5 volts over a min or so.. I have tracked it to the coil as i have disconnected everything else.

If i disconnect the coil and turn ign on the voltage on the lead is 12.6 v. Only thing i can think is that its the condensor??

Also are the connection from the generator connected the same way on the voltage regulator for -ve earth as a + ve earth. Cause i have tried both ways, The inncorrect way produced smoke at the generator.

I read about and polarized the generator, when you do this should the generator actual spin.. Testing the genny i get about 30 v off the small connector ( is this the ammetur or the field). Is this what i should get as the setup ss not charging the battery.

The tractor runs fine but the voltage at the battery is about 9 volts, so something is wrong.. and i cannot start it with the start i need to hand crank it...Hope this is all clear ( as mud).


I ve been at it all day and need some fresh eyes to help me out.

Ta :D
 
(quoted from post at 00:15:59 05/14/15) Hi all

Ok I have a 12volt -ve earth tractor, It has a 12v generator and starter motor, both are lucas, so assume its a 12v setup not a conversion . I have checked all the cabling and i did have to fix the regulator ( which i still need to test.) I used a wiring diagram from YT for checking the cabling.

However when i flick the switch (ign on) it seems the coil is dragging the voltage down, you can see the meter slowly discharge from 12.6 volts down to about 5 volts over a min or so.. I have tracked it to the coil as i have disconnected everything else.

If i disconnect the coil and turn ign on the voltage on the lead is 12.6 v. Only thing i can think is that its the condensor??

Also are the connection from the generator connected the same way on the voltage regulator for -ve earth as a + ve earth. Cause i have tried both ways, The inncorrect way produced smoke at the generator.

I read about and polarized the generator, when you do this should the generator actual spin.. Testing the genny i get about 30 v off the small connector ( is this the ammetur or the field). Is this what i should get as the setup ss not charging the battery.

The tractor runs fine but the voltage at the battery is about 9 volts, so something is wrong.. and i cannot start it with the start i need to hand crank it...Hope this is all clear ( as mud).


I ve been at it all day and need some fresh eyes to help me out.

Ta :D
ave that battery load tested. If it drains that fast and doesn't melt stuff, it can't be in very good shape.
 
The 12 volt was first used in the TEA at S/N 200001. So if you know the S/N of your unit you know if it is original or converted.
 
Change the cables. Most- if not all 12 volt systems are negative ground/earth. Seems your gen is making 30 volts pos, so I think the whole thing needs to be flipped to match.
Just don't cook that Lucas 12v, what is it there? $400 au? Be careful, good luck.
 
battery check out all good...

So recharged battery and cleanned and check more cables its turing over, still need to sort out the generator for charging

On the genny is the small terminal the ametuer ??.
 
Sounds suspiciously like you have a 12 volt coil with an inbuilt resistor that reduces voltage to six or thereabouts .
Theory is ; cold cranking starters drain the battery and leave little spare voltage to power the ignition of six volt systems . The ballast resistor was used to allow 12 full volts to both starter and ignition at start up and then revert to 6 volts once the engine has started , this allowed the ignition to run at 6 volts and so not burn out .
Try a coil that is a straight 12 volt , with no internal resistor and no external one in the wiring . An external ballast is usually a porcelain block about 50mm long and 20mm square .
 
Hi. The coil is not the original. There is no external resistor. So not sure If it is 6 or 12v. But I get 12v at the Pont's so guess it isnt a 6v.

Battery seems to struggle after some cranking and l need to sort out the generator. But getting there. Had to deviate and rebuild the carby, float problem. Float had some petrol n it. So drilled a hole drained and sealed. Hopefully that'll do the job.
 

The large terminal should go to the ammeter. The other side of the ammeter then goes to battery +. Ammeter is measuring the charging current, flowing THROUGH it.
Jim
 
Hi.

Ok the tractor is a 12v -ve ground tractor from the factory.

Had generator on the bench and it seems to test OK. as per lucas doco and this thread here.http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=farmall&th=811423


However when i put it back on the tractor and tested between A terminal and ground on the generator the max output is about 7v, ( i cannot remember the reading i got on the bench)
0which would be correct for a 6 V gernerator. However this is a 12v generator, so i am a little stumped. Any ides what the problem could be or how to test.

My other option is to get a 2nd hand alternator ( i think this replaces the genny and regulator)

Cheers
 

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