Generator Question

td1928

td1928

Junior Member
I started to notice 0 amps on the ammeter at idle or when running at 40 mph speed. I checked voltage at the cutout input side at a fast idle and was getting less than 1 volt. On the cutout output side full battery voltage. I slid the cover back on the generator and could see a wire had rubbed thru against the armature. I was able to take the generator apart, removed one field coil and solder and heat shrink the broken wire. The broken wire was the feed for the adjustable 3rd brush. Put it back together and after adjusting the 3rd brush to its max I was now getting approx 5 amps on the ammeter, but only about 3-4 volts on the generator output lug. I'm using a digital meter. The Les Andrews writeup states you should have 7+ volts on the generator output side. Thoughts?
 
You need to use an analog meter. Digital meters have a lot of interference. Measure voltage at the battery at idle, should be about 6.3v. Then run the engine up to 800-1000 rpm and again measure at the battery. It should be higher. 6.6- 6.8v depending on RPM. If it doesnt change, there may be a problem with the generator or cutout. Temporarilly put a jumper around the cutout. If it starts charging, the cutout is the problem.
 
I think there is a good chance that the generator was damaged when the wire rubbed through. Check the cutout as NDNCHF talked about in Post #2 first. If that does not solve the problem then you might have a damaged armature. Other problems may be the battery or electrical connections. If your ammeter indicates a charging current then you should see an increase in voltage at the battery.
 
Thanks for the suggestions. I used an analog and did see a slight increase in battery voltage from idle to fast idle. I checked the resistance of the cutout from output to case and output to input, both showed open circuit. I put a jumper from output to input while running and noticed a slight increase in charge.
What's perplexing is the fact that I am showing a charge on the ammeter, but 1/2 voltage on the input side of the cutout and full voltage on the output side.
Not sure if this had any value but I removed the cutout's input side and isolated from the generator and when running got zero voltage on the generator output side and of course zero voltage on the cutout output side.
Thinking the generator is toast?
 
td1928 said:
I Put it back together and after adjusting the 3rd brush to its max I was now getting approx 5 amps on the ammeter, but only about 3-4 volts on the generator output lug. I'm using a digital meter. The Les Andrews writeup states you should have 7+ volts on the generator output side. Thoughts?
Click to expand...

5 amps must be discharge. 3-4 volts will keep the cutout open.

Bad generator.
 
Its hard to say with examining it closely, but as mentioned earlier, the wire wire rubbing the armature may have electricalled compromised something.

You are welcome to send it to me for testing and repair. PM me if interested. I will be at Hershey. You could drop it off there.

Steve
 

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yes, I have moved the third brush from min to max and still only have 3 volts on the gen output lug when in the max position. Have sent it along to Steve B for testing and rebuild
Tim
 
Just a final update.......I sent the gen and cutout to Steve Blancard in Virginia. Steve tested both and found issues with both the generator and the cutout. He repaired the generator and replaced the repro cutout with an original rebuilt. He sent along a few pics and a video of the generator operating on his test stand. Both have been re-installed in the Tudor and work perfectly. Now getting a good 4-5 maps charge on the ammeter and a strong 7+ volts on the cutout input side.
I would strongly recommend Steve if you have a gen or cutout issue. His turnaround time was excellent
Tim
 
Glad I could be of service.

To summarize the problems found:

The repro cutout had an insulation breakdown causing an intermittent short. Replaced with a refurbished original Ford cutout.

The adjustable brush was installed backwards. Therefore making minimal contact with the commutator.

The + brush had big chips out of it, a new brush was installed.

All brushes were then sanded in to match the commutator.

The brush plate bearing was loose on the shaft. Secured with Loctite bearing retainer.

After these problems were rectified it was bench tested up to 14 amps, then set back to 4-6 amps for normal daytime driving.

Steve
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