My generator has lost it's mind

oldbike99

oldbike99

Senior Member
My long style generator has suddenly started needing to be "re-polarized" each morning in order to charge. Brushes, battery, wiring and ammeter are all fresh. I use a stock style cutout. The connections, including the brushes, are clean and snug. The battery never goes dead, the car starts and runs great and the ammeter behaves normally, after briefly connecting the cutout terminals. The next morning, I have the same trouble.

I am at a loss. Any suggestions as to how to correct the problem?
 
I don't know if this is possible but could it be the points in the cutout
aren't closing and when you jump it the points close.

Bob
 
Once magnetized the soft iron of the fields should retain their magnetism for quite a few years. Just take a look at a screw driver that you have magnetized and it hold that magnetism for a long time. I think you have a bad cutout.
 
What is happening upon start-up ? Is it just not charging, or, discharging heavily ?

Is the cut-out an original or a repo without a regulator or diode ? If its an original have you cleaned and adjusted it ?
 
I have a stock cutout without a diode.

Upon startup, it has a slight discharge. Once I connect the terminals momentarily, it will begin charging normally, even if I shut the vehicle off and restart it.

The next morning, it is back to a no charge condition.

I will need to do some research into how to clean and adjust the cutout
 
Use an analog volt meter and check the voltage at the generator output post as soon as you start the engine and have it running at fast idle with no charge showing. If it shows more than 6 volts, the problem could be the cutout or some bad connection. If the voltage at fast idle is less than 6 volts the generator has a problem and you won't need to mess with the cutout (at least not yet). Your armature might have a slight short to ground and be draining off the voltage. I've had this problem with a cutomers generator a couple years ago, and another armature fixed it.

You can do your own continuity check even with the armature installed, but you will need to slip paper under each of the 3 brushes first. Then use your ohm meter and touch the commutator and ground. It should show open (infinity) on the ohm scale. In other words, the meter needle shouldn't move at all.

To do the rest of the checks on the armature you will need to use a growler.

As long as you have paper under the field brush (the adjustable brush) you can also check the field windings. Clip a 6 volt battery charger + cable to the case, and clip the - cable to the adjustable brush (field wire). The charger amp meter should show about 4 amps draw when using 6 volts.
 
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Great pictures!! I took quite a few as well. I posted them on a blog I'm starting (really to show my grandfather my Model A adventures). Feel free to take a look if you'd like!

http://fordsladya.weebly.com/

Overall, the show was great! There was a great turnout and I met some really cool people. Thanks to Beardsley Cider Mill for hosting!!

Joe
 
There appear to have been two different problems. One was a very slight misalignment of the output brush with the commutator, resulting in slightly low generator output. This, combined with a cutout whose " cut in " voltage was set slightly too high, resulted in the erratic charging issue.

Thanks go out to all that helped, especially Tom Wesenberg, who took the time to email me several times to talk me through the necessary procedures.
 
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