Dead Generator, perhaps?

Father Mike

Father Mike

Junior Member
Greetings all;

I just wanted to run this by you to see if I'm on the right track. I don't know much about electrical systems and I see that there are quite a few posts concerning generators, cutouts and the like which I have read thoroughly. However, this question is for my own confirmation and/or a star chamber discussion.

I feel I may have found a problem with my generator recently because of no positive amp reading during any driving or idling. Whether at low, high or in between RPM's there's no positive charge. I have a clear discharge when the lights are on or the horn is signaled as would be expected. When I first got the car, the amp meter would read positive only at high rpms and even at times maintain a charge while driving however spotty. Yet recently there is nothing, zip, zilch, nada. When I first got the car, I had no clue as to the third brush but I have attempted to adjust it several time since this problem has surfaced with no results. Here is what I have done so far...

1. I tried to re-polarized the generator, however there seems to be no response from the generator when I do this. No motorization, no spark, nothing.

2. The cutout shows a 6v+ on the wire side to terminal box and no charge on the bolt when the car is off. (as would be expected) When the car is at idle, it shows the same thing... nothing coming from the generator. When the car is at high rpm, again it shows no reading from the bolt side of the cutout.

3. Hooked 6v battery charger to the generator directly while freed from the fan belt with negative to generator and positive to ground. No spark or motorization.

4. Turned the car on and pulled the after-market fuse on the starter to see if the coil was being charged by the generator or the battery and the car went dead.

My question is; have I done enough to single out the generator as the point of failure? I've inspected the cutout and it seems fine. (no stuck point, but I haven't check the gap yet.) All the electrical components are working fine and are well grounded. The lights work, horn works, brake light works all showing the same negative discharge on the amp meter whether driving, idling or off.

Any suggestions or directions to go would be greatly appreciated. Thanks in advance.
 
The generator is definitely the problem. Sounds like you know how to test the system and if everything you say is correct your generator has failed.

Repair or replace your generator and please keep it (my opinion) 6 volt.

Pete
 
It could be something as simple as a dirty commutator.Hold a piece of fine sandpaper-not emery paper-against the commutator while the engine is idling and it may start charging.If so,you can adjust the charging rate by moving the 3rd brush by pushing it down to increase the charging rate or push upward to decrease it.I set mine to show a charge of about 5 amps as I do most of my driving in the day time.The less amps you can get by on,the easier it is on the generator.
 
It could be worn brushes or burned armature, since you said it showed some charge not so long ago, but now none. If the output stud is on the front of the case then the output wire is taped to the side of the field winding, and this makes it easier for someone to mix up the field wire and output wire when reassembling the generator. If these two wires get mixed up on the adjustable and output brushes, the generator can get cooked! I've had to work on two generators that came from "professional" repair shops and were cooked by having the wires mixed up.

If the brushes look good then check the field windings by connecting a 6 volt battery charger to the case the the field wire that goes to the adjustable brush. The charger should show about 4 amps. If that's OK, then check the armature on a growler.
 
Marc, if my understanding of the system is correct (and it may not be) when testing the system with my cheap analog tester, I switch the probes so that it reads positive instead of negative. I put the red positive on ground and the black negative on the device. It gives me a reverse reading of positive, although in actuality it's negative. Since my Radio Shack voltage meter doesn't read in negative, if I hook it correctly it just buries the needle toward the left with no reading actual reading except the knowledge that there is a charge.
 
Father Mike said:
Marc, if my understanding of the system is correct (and it may not be) when testing the system with my cheap analog tester, I switch the probes so that it reads positive instead of negative. I put the red positive on ground and the black negative on the device. It gives me a reverse reading of positive, although in actuality it's negative. Since my Radio Shack voltage meter doesn't read in negative, if I hook it correctly it just buries the needle toward the left with no reading actual reading except the knowledge that there is a charge.
Click to expand...

Since the car is + ground and you have the red + probe grounded, you are hooking it up correctly.
 
Coincidentally I had the same experience this past Friday. We thought it may be a bad cutout but after trying a friends' spare cutout and not seeing a difference, we ended up looking at the generator.

It ended up being the wire to the third brush broken from the clip so no charging was taking place, only discharge when the lights were on.
A little bit of soldering and it's back in business!

My buddy mentioned that he's experienced the wire connecting the cutout mounting bolt break and you see the same problem with the zero charge reading on the ammeter.

Hopefully, your issue is just one of those wires that can be re-soldered.
 
Reverseing the battery cables or testing the generator with negative ground , can and will reverse the polarity of the generator. If you are using an original style cutout instead of a can style voltage regulator, you can jump a wire across the posts of the cutout for a couple of seconds, to repolarize the generator. If that doesn't work, the field and output wire could be reversed inside the generator as Tom said above . Either of these problems will not allow the generator to charge and adjusting the third brush will make NO difference .
 
::Update :: Today I decided to make one final test of the generator. I called a professional generator/alternator man a couple miles away to put it on his 60 year old machine. He hooked it up, attached a faux fan belt, flipped a few switches and behold, lots and lots of power from the generator. (The third brush was all the way down from my farting around with it). I left it with him for some cleaning and a once look-over of the innereds. (I'm sure it hasn't been touched in at least 4 decades).

To heneste, when I removed the dust band I noticed my wire to the third brush looked a little bad. It doen't look well soldered. That too could be a problem. Thanks for the idea.

So I guess I may need a new cutout after all. A bad cutout would no not allow the power from the generator to reach the battery or the rest of the system but it still doesn't explain why I had no reading from the generator output, does it? Any ideas?
 
After being untouched for 4 decades, could be many things causing it to function intermittingly; however, great news to hear you got it charging & are getting sincere professional assistance.
 
Sometimes too long a screw gets used for the cutout terminals and it might short to the coil inside. I've also seen the insulating washers get left off the cutout terminals, or the wire terminals touching the cutout case.
 
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