TR2/3/3A TR3 Generator ... not working

[mgedit]

Got car running and idling reasonably well now, but generator issues remain. Red light glowing brightly. Generator was rebuilt by knowledgeable friend who has since passed away. Took it to an old-fashioned generator shop that quickly checked on it on his test machine and indicated it was charging. Took home, installed in car, and still same issue. Using test manual, I started to do diagnosis. Test 1, both leads off generator, and voltmeter on D get reading about 3.3 V at "speed", which suggests armature and brush connections are OK according to manual. Next test, jumper F and D terminals and check voltage at D to ground. Getting reading about .2 V or little less, which seems to indicate grounded field coils or field connection. The F connection seems a bit loose at generator. Might this be where the issue is? Any suggestions are most welcome. I will take generator out again, and happy to take to shop to have him look at it again, but just wondering how I can bench check to see if it is something I can easily fix myself as it is a bit of a drive to the shop. Cheers, Mike

 

[mikephillips]

I'd ask if they can test the generator and regulator as a pair, years ago that was the way I was always told to do them since together they form the charging part of the electrical system. You want to be sure than not only is the generator working but that the two coils in the regulator are connecting/disconnecting properly. Take along the wires from the two as well, could be an internal fault there too and then you have the full system checked.

 

[TexasKnucklehead]

Although testing the wires seems like a good idea, removing the wire harness is a lot of work, and only 2 wires go to the generator. If i were in your situation -and I was this past week, I would down load the Lucas electric booklet and/or refer to the bently manual. With the 2 wires removed from the genetator, make an electrical connection to both points and the hot side of a voltmeter. The other side to ground and engine running (low rpm) you should see voltage generated, telling you you do not need to remove the generator again.

My problem was dirty contacts in the voltage regulator and missadjusted regulator.

 

[mgedit]

Thanks guys. Agree that removing the wires is not going to happen as I have a new wiring harness. Did start the diagnosis steps with Lucus electric book and manual. All connections are clean so I'm inclined to think something is up with generator. Have it out now and will head to shop today to see if he can sort out. Cheers, Mike

 

[M_Pied_Lourd]

Mike, think I have a couple spares if need be...I suspect that you might have a back up or two as well though.

Cheers
Tush

 

[TomMull]

I wonder if the bench test used positive or negative ground? Perhaps was polarized to negative? I'd try re-polarizing. Tom

 

[mikephillips]

I was really only thinking of the two wirs from the generator to the regulator. In my other cars they're a separate bit of the harness, I'm gathering that in the TR they're not. So while in general terms testing would be the same from make to make, this is a detail difference.

 

[TomMull]

Next test, jumper F and D terminals and check voltage at D to ground. Getting reading about .2 V or little less, which seems to indicate grounded field coils or field connection. The F connection seems a bit loose at generator. Might this be where the issue is? Any suggestions are most welcome. I will take generator out again, and happy to take to shop to have him look at it again, but just wondering how I can bench check to see if it is something I can easily fix myself as it is a bit of a drive to the shop. Cheers, Mike

Not sure I understand here but this test is independent of the regulator and should be at 13 -14+ volts (might be higher as the generator is completely unregulated. Bad regulator or wiring (outside the generator) will not cause this failure. A bad field connection on the generator will, of course, but it unit seems to have passed more than on bench test. If it was tested and polarized by the re builder as a negative ground unit, which is not unlikely, it will not generate with positive ground wiring until it is re polarized. Not saying that this is your problem but I think it's a possibility and quite easy to check and fix. Tom

 

[mgedit]

Thanks all. Took it back to the shop, and it did not charge at first, but after "excited" it starting charging again. He is going to take it apart to double check everything and I'll get it back Monday. Was working as positive ground BTW.

Mike ... Checked continuity of those wires and they are fine, but are wrapped in new harness.

Tush I do not have a spare, but might be able to track one down locally. If not, don't through any out

Tom, was following Luca fault diagnosis manual for generators and regulators ... step by step until I got bad reading on step 2.

Cheers, Mike

 

[TomMull]

Glad you git it working, Mike. Fault finding was correct, no charge from generator identified at step 2. "Exciiing" the generator is another term for polarization. I guess I should not have assumed that the process was as well known now as it war 50 years ago. Simply remove the field wire from the generator and touch the field terminal with a hot jumper (can do at regulator too). In this case negative. Most rebuilt generators won't need this step if they have been polarized at the bench but they certainly will if they've been polarized to negative ground and then installed on a positive ground vehicle (they will charge either way but require re polarization). This, it would seem, happened on yours.
Tom

 

[mgedit]

Thanks Tom. Just got generator back from shop. Hopefully, all will be OK now. Cheers, Mike

 

[angelfj1]

Mike, make sure that the rear bushing is not dry. There is a hole for oil and a felt inside to absorb the oil. This lubrication is critical although often neglected!

 

[mgedit]

Thanks Frank. Good point. Cheers, Mike