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Re: [T3] Signs Point to Bad Generator


on 15/4/2003 10:01 AM, Martinez, Leon at martinezl@ftscpac.navy.mil wrote:

> Anyone know what may have happened to this and other generators, any
> experiences ?

I just went through the whole generator thing; I will tell the story from
the start.

I was driving along a few weeks ago, and suddenly smelled smoke. I saw it
coming from under the dash, and traced it back to the regulator. The plastic
on the bottom had been burning.

I disconnected the regulator, and took the pulley off the generator and kept
on going on battery power. Later that day, I took it to an auto electrician
to see if they had any regulators in stock. They didn't but offered to check
the generator for me. When I opened the engine lid, the auto electrician
noticed that the D+ wire had come off the generator terminal and was
shorting on the body. He put a new connector on there for me, and I put the
pulley back on and hooked up the generator again while he went and got the
generator tester. He put that on, and found that it was now charging at up
to 17V.

This was no good, so I disconnected it again, and the next day I went to the
VWFLAPS and got a new regulator. I did Jim's tests to check that the gen was
putting out voltage, and also checked the armature for shorts and the field
coils for continuity and that all checked out fine. I put the new regulator
on, and found soon after that it kept on clicking, although it was
regulating at 14.4V OK.

I drove around that day, but it still kept on clicking so the next day I
took it back. They said that they had one other that did the same thing, and
it was just assembly oil on the points from the factory. They cleaned it,
and I reinstalled it again, but it was going up to 17V again. They gave me
another new one and I installed that and it regulated at 14.4V and didn't
click. Problem solved, or so I thought.

I drove round for about 3 days with a multimeter sitting on the passenger
seat, so I could keep a close watch on the voltage. It was fine, so I
thought I had solved the problem. Except, one day I smelt that smell that
batteries make when they are fully charged. I felt the battery and it was
quite warm. I hooked up the multimeter again, and found that the voltage had
crept back up to 17V again!

In the meantime I had bought a couple of T3 generators off the internet, so
I got new brushes for one of them and took it apart and cleaned it all up,
and put that in the car. I did the generator tests, and that all checked out
fine. I hooked the old regulator up (the one that was originally in the car)
and tested it. It runs at a constant 14.4V at mid RPM, and has been for 5
days now. Hopefully this time I have fixed it.

I can only assume that one of the field coils in my old generator got
shorted out when the D+ wire came off (which would have caused the field
coils to get full voltage) and this caused the generator to always run at
full output. 

One thing I did notice on the 'new' generator I put in, was that the
soldered connection between the two field coils had become unglued from the
piece of insulating plastic it was supposed to be stuck to. I glued that
back and put some shrink sleeving over the screws that hold the generator
together because I noticed they could also touch the wire that goes between
the +ve brush and the field coils. So here are two possible places for
failure to occur.

This was on the older(?) style of generator with the push on terminals. I
also bought one of the newer style with the screw on posts and I noticed
that they had routed the wires a bit differently in there, to avoid these
problems.

Ben Doughney

'75 1200L
'63 1200 - Ringo
'71 1600TL

http://members.tripod.com/~superkafer/ 

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