Does anyone here know automotive generators?

[widebody911]

I have a 1963 Type 3 Karmann Ghia (aka T34), and I've rebuilt the engine as well as installed a rebuilt 6v generator. When the generator runs, it puts out a lot of sparks and light. It's putting out between 7v and 8v, and is not triggering the idiot light when running. I even tried it with the positive terminal disconnected, and it still sparked. I tried revving it up pretty high ; I don't have a tach, but it's a stock rebuild, so it couldn't rev too high and the sparking stopped... because one of the brushes popped off the commutator.

This is the second generator that's done this; the shop that sold me the rebuild sent me another one when I told them about the problem. Now that two of them have done it, I wonder if somehow it's my engine that's causing the issue, or if I got two bum generators in a row.

What would cause this behavior?

[schamp]

Is this a negative or positive ground car?

[widebody911]

Originally Posted by schamp

Is this a negative or positive ground car?

Negative ground

[Rot 911]

Did you polarize the generator?

[widebody911]

Originally Posted by Rot 911

Did you polarize the generator?

Yes

[jwgn777]

Carbon brushes often make sparks when breaking in on a freshly cut commutator. Perhaps there not installing them correctly You did say one of the brushes popped out. Try another re builder. You said every thing else was working fine.

[id10t]

My Dad's 60s vintage Sears drill does the same thing. However, I've never seen sparks like that on my 356c's gererator and they are the same bosch part....

[wdfifteen]

Great photography! That's not normal, but there isn't anything your engine could be doing to cause it. If you have a good 6 volt battery and a good voltage regulator it shouldn't do this. If it was only one generator that did this I would assume the brushes/commutator weren't making good contact, but it's hard to believe more than one generator would have this problem. I my guess is there is an issue with the voltage regulator. Voltage when running over 1000 rpm should be 6.9 or thereabouts, not 8.

[Rick V]

Great pics.
Does it make any noise or did it feel funny before you installed it? The color of the sparks almost looks like a bushing is grinding itself away

[intakexhaust]

Rebuild from China.. what do you expect?

All fun aside, guessing you have to check the brush springs, brush alignment in the carrier. Also, does the armature have too much end play where it might knick a brush and throw it?

[FLYGEEZER]

How did ya "flash the feild" or polarize the generator ??? Good pics by the way.

[Hugh R]

Been a while with generators, and mostly Lucas. Check out the cut-in/cut-out voltages on the regulator magnetic coils for the field windings. With Lucas, you can turn some screws to change them. Not sure on German trash.