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MG TD TF 1500 - electric again

Need your help again.
After an 2 hours ride the red light on dashboard comes on. Have no idea why ?
I have checked the generators brush but they are OK. Opened the regulator and pressed down the contact on first coil than the light switched off. I hold it down but after a while the light comes on again.
Now I will check the generator. I understand that the two terminals must be connected together and than the voltage has to be mesured from the terminals to ground.
Any further sugestion ?
Thank you
Guenter
Guenter

Guenter,

I e-mailed you a number of articles about troubleshooting charging system problems.

Good luck.

Larry
Larry Shoer

Thank you Larry,
I'll make the trouble shooting by tomorrow and will report the results.
Cheers,
Guenter
Guenter

When I first started the TD, the light stayed on all the time (I know, this is different), but for what its worth, i took the gen apart and cleaned out each of the slots on the computator (sp) and all has been well since....!
gblawson(gordon)

Thank you again Larry,
I checked the generator as you described but found not a clear result. It was measured something in between 0,05 and 0,4 VDC while turning by hand. Next test was to measure the generator output. I found only 0.55 VDC on idel speed (600 rpm) at the same configuration with both terminals short and measured from there to ground. Sure the speed was low but I understand in this configuration there should be 14+ VDC at 3000rpm.

Therefore, I removed the generator from the car and than the brushes from generator. Cleaning everything and assemble carefully together again. After that excersise the values were 1.4 VDC with one brush installed and 2.8 VDC with both. Sounds good and is more or less according your specification.

Next, it was installed into the car again. Checking the generator output but this is still low. I found something below 1.0 VDC and on higher speed it climes up to 1.9 VDC but not 20 VDC as specified by David DuBois in an earlier thread found in the Archive.
Consequently, I have to accept that the Generator is down and need repair. But how can I do that ? what is needed ?
Thanks for your help down the road.
Guenter
Guenter

I recently repaired a charging system problem with my TD that was corrected by replacing the generator brushes and cleaning associated parts.

Guenter appears to have good brushes in his generator, but the generator still does not produce expected electrical output. This goes beyond my knowledge of the generator and I'd ask others more knowledgdable to step in.

Thanks.

Larry
Larry Shoer

I found further Informations for testing lucas generators:

http://freespace.virgin.net/tommy.sandham/dynamo.htm

The test in first portion lead to the assumption that a field winding fault could happen.
Next step is to measure the field winding resistance between terminal "F" and ground. The result on my generator is 6.6 Ohms, means the field winding is still OK.
What can I do next ?
Guenter
Guenter

Guenter,
Are you sure that there isn't something else on that is drawing electricity, or maby a short which is making the gen work overtime, and there for the red light?????

SPW
Steve Wincze

I woul suspect the test where you connected the outout of the dynamo to the F connection on the dynamo. You may not have had a good connection between them. Make sure this is a good connection. Connect the voltmeter to this junction and to the case of thy dynamo (ground) and run the engine you should see the voltage increase as you increase the engine speed as detailed in your Lucas test.

If no result, send the dynamo to be rebuilt or get a replacement.
Don Harmer

Guenter -- Make awfully sure that the field terminal is well insulated from the case and that the ground connection for the field is good and solid. It is my guess that one of these two connections is failing and the output will go to close to zero.

Your measured 6.6 ohms is close to the Lucas specified 6.2 ohms so the field coils are OK. It has to be a connection to the field. If the field shorts to the case there is no current in the fields and no magnetic field, therefore no output.

Be sure that the wire that connects the two field coils is not shorting to the bolt that holds the end plates on the case. This is easy to fix, put heat shrink tubing on the bolt.

Keep us informed of your progress in finding and fixing your problem.

Cheers,

Bob
bobj50

I have inspected the generator again and found some soldering lead in the cutout windows. Further examination shows that the solder lead comes probably from the armatur. I don't know why but anyway, this is a matter of fact.
Consequently I have to replace the generator.
I called Moss Europe but they do not have the Dynamo in stock and delivery is forecasted earlies in October. What can I do ? Has anybody an other source for a new / rebuild dynamo ?
Thanks again for your help.
Guenter
Guenter

My generator failed some year ago and a local firm of electric motor rebuilder did a good job quickly and for little cost.

Try a local search for generator repair and rewind service. That should do it.

IanB
IanB

OK, I found a supplier in German who has a refurbished generator in stock and will deliver what I need.

My question now to the experts:
What could be the reason for this failure ? I understand the generator becomes hot, my be to hot and the solder melt and was pushed away. But what can be the reason that the armatur becomes to hot ?
I run the car last year in North Carolina during sommer periode with outside temperature between 90 and 100F without trouble. Now I made a short trip just two hours from my new hometown with outside temperature of 65F and the solder on the armature failed.
Can it be that the new battery is the reason for this trouble. I decided beginning of this year to replace the old one by a Red Top Optima.

Will it be better with a solid-state conversion Regulator offered by Bob Jeffers ? I have this regulator availaible but not yet installed. Should I do that or should I stay with the old fashion one ?

Thank's for your sugestions.
Cheers,
Guenter

Guenter

Guenter -- As I understand, the solder will melt and get thrown out if there is a short in the armature windings. This can be found with a "growler" Which is a device that puts a 60 cycle magnetic field through the armature, Then with a hacksaw blade or similiar piece of metal you place the blade near the armature. If it vibrates there is a short in the armature windings. If it is relatively free of vibration there are no shorts in the armature. Then you test from the commutator to the shaft with 120/240 volt AC and a light bulb in series. If the light bulb lights then there is a short to the laminations or the shaft itself. In either case the armature must be rewound. Here in the states there is a company, Holcombe Armature Co. in Villa Rica, GA. that will rewind the armature. Phone No. 1-800-241-3027 they may want your kaput armature to have the correct laminations.

I would not suggest that you use the solid-state regulator until you get this problem straightened out.

Sincerely,

Bob
bobj50

OK Bob,
thanks for explanation. This make sense to me.
That means with a new generator the problem is solved and no or very limited risk to get this failure again.

In that case with a new generator I can go with the solid state regulator. Right ?
Cheers,
Guenter
Guenter

OK Bob,
thanks for explanation. This make sense to me.
That means with a new generator the problem is solved and no or very limited risk to get this failure again.

In that case with a new generator I can go with the solid state regulator. Right ?

Oh, by the way can it be that the different humidity can be the reason for all the trouble in the electric equippment I never had before ?
Some two weeks ago I found that the ignition coil don't deliver sufficiant sparks and the engine was not running. Now the Generator. It's strange, is'n it ?

Cheers,
Guenter
Guenter

I would replace the regulator!
Chances are that the armature problem was caused by the regulator.
( applying full voltage to the field coil all the time causing it to produce excess voltage)
Our local Guru's Rule: If the generator fails, replace the regulator or you will have to replace the new generator soon)
Don Harmer

This thread was discussed between 06/08/2008 and 08/08/2008

MG TD TF 1500 index

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