Not Charging - what's up?

Do you have an analog meter to do the checks, instead of the digital. The electrical "noise" of the Model A can mess up the readings on a digital meter.

With the engine at fast idle, measure the voltage on the battery cable clamp, then probe the battery post. If the voltage is different, then the posts/cables need to be cleaned. I find it hard to believe that this is the case, since the engine cranks and runs fine, but so far the readings have led to this point.

At any connection when you have a change in voltage, with current flowing, you have found the problem. Or at least one problem. If you have two problems going on at the same time, it makes trouble shooting much harder, or more confusing. You must have current flowing to measure a voltage drop, so you need to be running the generator, or turn on the lights when the engine is off. Either way will have current flowing through the wires in the charging circuit. However in the car in question, the voltage is so high that it would indicate an open in the charging circuit.

A visual is always a good way to start trouble shooting. Look for loose, frayed, or corroded wires and connections. Battery posts can get a dark hard coating which gives poor conductivity, so even though they don't look corroded, they need to be cleaned. I've had to scrap them shiney clean with the edge of a knife blade.
 
Walt Ebie said:
Good morning.....here's the early report: I checked all the above, Tom, and here are the results: First, the generator ground looks good with no rust that I can see. Then, with engine OFF: Output side of the cutout, both terminal posts, both sides of the fuse, the starter switch, the ignition switch and both ammeter posts all show @6.3V. The only exception is the generator output shows 0V. Then with the engine ON, running at a good idle: All the same points show @18.3v. Also behind the instrument panel: there is NO black/blue wire from the terminal to power the wipers and dome light. Instead, there is a gray wire from the Ammeter discharge side that apparently does that. Although the instrument light is connected to the AM charge post, if I remove the gray wire from the AM-dischg post neither the instrument light nor the dome light will work. If I put the gray wire on the AM-chg post, again no lights. But as long as the gray wire is on the Am-dischg side, all the lights will work and the instrument light will work on either Ammeter post.[/QUOTE]

Something does not seem right with this ,shouldn't the lights work hooked
to either side of the ammeter?

Bob
Click to expand...
 
"Something does not seem right with this ,shouldn't the lights work hooked
to either side of the ammeter?

Bob"

Yes, they should.
I wouldn't worry about the dash light though until the charging system is working correctly.
 
Tom Wesenberg said:
"Something does not seem right with this ,shouldn't the lights work hooked
to either side of the ammeter?

Bob"

Yes, they should.
I wouldn't worry about the dash light though until the charging system is working correctly.
Click to expand...

Tom, wouldn't the fact that the dome light only works when connected
to one side of the ammeter and not the other indicate a problem with
the ammeter and a possible open in the charging circuit?

Bob
 
Bob C said:
So why won't the dome light work connected to either side of the ammeter???

Bob
Click to expand...

Exactly.
That's why I keep saying a lot of things just don't add up.
I'm waiting for the punch line that this was just a joke to see how long before we figured it out.:D:p
 
Good evening All, and thanks again for all your help! I think some progress is on the way. I put the digital VM on the shelf and went out and bought an Analog type. The attached picture of the results will show things a little more as they no doubt were all along. Anway, here are the numbers. But there is no charge showing on the ammeter but that may be corrected by a new one. What do you all think now? Is it normal for the gen output to be that much smaller than the cutout output? I did move the 3rd brush about halfway down in the generator but it still showed 4.2. It was at the top for the figures in the chart. Hope this helps.
 

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So now the generator isn't working.
Test the generator cutout again on both sides, and try both meters to check one against the other.
 
Okay, here's the morning report: First, I checked the voltages as you suggested at the battery clamp and post: at fast idle, I get 6.3v at both. Then I checked the gen output and the cutout output with both meters: with engine OFF both meters read 0 at gen out and 6.3 at c/o out. Then at fast idle: digital gives me 0 at gen out and 18.3 at c/o out; analog shows 3 to 4v at gen out and 6.3 at c/o out. I'm sure the digital does pick up on what I guess is electric field noise because it will show fluttering voltages even if not hooked up but just close to the engine or battery. I read in one of Andrews' books that moving the third brush down would increase the output voltage so in addition to the above I moved the brush almost all the way down and it didn't make any difference in the gen output.
 
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This is why I wanted you to use both meters, and this is why I don't care for digital meters, especially around older cars.

The adjustable brush controls the amps, but not the volts. To control the volts you need a voltage regulator. Anyway, right now you need to have the generator repaired, because the output is too low. You may have thrown some solder from the commutator while running it at the high voltage, or you may have burned some windings. If you don't feel comfortable working on it, at least remove the band and look inside and smell for burning.
 
I don't think I would work on it myself - not really knowing exactly what to do - but I'm only an hour from Snyder's so I may have to go for a rebuilt one. Also I've had a persistent water leak at the pump - not unusual, I know, but I did repack it with the rope-type packing which worked for a while but I tightened the jam nut periodically to try to stop the leak and now the nut is about maxed out again. So I'm thinking about trying the other type that uses 2 pieces of graphite packing. Do you have a recommendation on that? Do most people use one or the other? They're both pretty cheap but I just wondered what most people tend to use.
 
or you can send your generator to tom for a rebuild and at the same time he can install his internal voltage regulator (EVR)....:)
 
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