Generator testing and wiring

[mountinpie]

I've inherited a 1930 Model A that's been partially restored. I've replaced some of the wiring (including the yellow/black to generator) and got it running, but need to understand the generator to get it charging. I'll likely take it to a local shop for testing/repair, but would to test/fix myself if possible. I really don't understand continuity, which wires to test and how, or even how the generator gets wired to the car. Can anyone offer help in very basic terms? Thanks all!

 

[JohnLaVoy]

If you have the generator off the car a simple test is to hook 6 volts to it and see if it motors (runs like an electric motor). If it does then when hooked up it will generate but you will need to make sure the cut out is correct the wiring is correct and that you have polarized the generator to the car. All of the instructions for wiring are in various books. The motor test is the simple one I use to see if the generator needs to be rewound etc.

 

[mountinpie]

I'll try that, but how/where do I hook the battery? In the picture I included, you'll see that the generator has 2 wires coming out of it, instead of a terminal post. I'd like to test it first, then order anything I need for a proper connection/repair.

 

[mountinpie]

Ok thanks. So when testing with a 6V battery to see if it motors, I connect the positive terminal to the grounded screw and the negative to the cutout armature side?

 

[Tom Wesenberg]

Ok thanks. So when testing with a 6V battery to see if it motors, I connect the positive terminal to the grounded screw and the negative to the cutout armature side?

Correct, and it should spin slowly in the same direction it will turn when mounted on the engine.

 

[mountinpie]

Thanks Tom. I tried that yesterday and just got a little hum/whine from the generator, no turning. Decided to take it to someone who knew a little about generators and they said it tested fine, but they'd install a terminal post and give it a good look see. I also have a spare generator that I'll get repaired and keep on the shelf. Thanks again for the help!

 

[David Rosellle]

I have 1929 Model A. The generator bench tests at 7 volts. When on the car the voltage jumps from 2 to 10 volts constantly. I jumped from the battery direct to the positive side of the generator same result. Please help.

 

[Tom Wesenberg]

I have 1929 Model A. The generator bench tests at 7 volts. When on the car the voltage jumps from 2 to 10 volts constantly. I jumped from the battery direct to the positive side of the generator same result. Please help.

The Model A generator is an unregulated generator, and if the 6 volt battery isn't connected to it the voltage can go as high as 40 volts, which will soon fry it. If you show 10 volts while connected to the battery, either the battery is too small, or shot, or the generator is set for too many amps.

To decrease the output, you move the adjustable brush up.