12V generator not working

[Robert Dip]

I purchased a '35 Ford generator ( fan mounted on pulley ) converted to 12 V. I use a '56 Ford 12V voltage regulator for this setup. The volt reg was sparked to polarize and the wiring is all correct. I have another Roadster with this setup, and all works great. On the '35, I just cannot get it to charge. All was done to find the problem and still not working. I ordered another volt reg, same problem. I swapped the reg with the one working on the roadster....still no go. I had the generator checked and the shop specialized in gens & starters told me it's fine 12V output at so many amps. I place the voltmeter at the starter solenoid and get the proper 12V reading until I start the engine...the meter reads all kinds of crazy numbers. Battery is in the trunk and with engine still running, it reads a solid 12V at the battery. Some say that voltmeters go haywire near the voltage reg box, but ???? I'm at a loss. Need help here to find the mystery. Thks in advance.

 

[bbrocksr]

I purchased a '35 Ford generator ( fan mounted on pulley ) converted to 12 V. I use a '56 Ford 12V voltage regulator for this setup. The volt reg was sparked to polarize and the wiring is all correct. I have another Roadster with this setup, and all works great. On the '35, I just cannot get it to charge. All was done to find the problem and still not working. I ordered another volt reg, same problem. I swapped the reg with the one working on the roadster....still no go. I had the generator checked and the shop specialized in gens & starters told me it's fine 12V output at so many amps. I place the voltmeter at the starter solenoid and get the proper 12V reading until I start the engine...the meter reads all kinds of crazy numbers. Battery is in the trunk and with engine still running, it reads a solid 12V at the battery. Some say that voltmeters go haywire near the voltage reg box, but ???? I'm at a loss. Need help here to find the mystery. Thks in advance.

Was this generator converted to a later two brush design using later 12 volt fields or later housing and fields or is it using the three brush design?
Bill

 

[Ggmac]

Use an analog volt ohm meter . The noise is making the digital go crazy . I foundthis out the hard way .

 

[cas3]

how did you change a 3 brush (35) case to the larger 2 brush case that requires a voltage regulator instead of a cut out?

 

[koates]

Yes much more information required regarding the generator and its modifications. The field coils in a Ford generator are controlled through the regulator to the Generator armature terminal. Some other generators the field coils are controlled through the regulator to ground. If the fields are connected wrong inside the gen then it wont work with a Ford regulator. To test your Ford generator using the original Ford regulator remove the field wire off its regulator field terminal and connect it over to the regulator armature terminal. Dont use a jumper wire to do this. The cutout inside the regulator stays connected. Start and run engine to 2000 RPM and check cars ammeter which should show a high charge. If no charge then the generator is most likely faulty. Report back for more info. Regards, Kevin.

 

[koates]

For the one hundredth time I will state that digital multimeters are not suitable for reading voltage or current on old cars that are fitted with generators or solid copper wire high tension ignition leads. Only analog meters (have a pointer dial) are to be used. A 12 volt battery should read approx 14 volts across its terminals when the car engine is running and the generator or alternator is charging. A 12 volt reading indicates that the battery is not being charged. A fully charged 12 volt battery at rest should read approx 12.6 volts. Regards, Kevin.

 

[Robert Dip]

koates......I will be looking into what you have stated. This gen has been converted to a two wire config. arm & field. I hooked it up to an auto mechanical gauge voltmeter with no indication of charging. Also reversed the A & F wires with same results. Just to make sure if the voltage was not high enough on the voltmeter, I disconnected the battery while the engine was running, and it died.

 

[koates]

koates......I will be looking into what you have stated. This gen has been converted to a two wire config. arm & field. I hooked it up to an auto mechanical gauge voltmeter with no indication of charging. Also reversed the A & F wires with same results. Just to make sure if the voltage was not high enough on the voltmeter, I disconnected the battery while the engine was running, and it died.

You should not disconnect the battery while the engine is running, but I know some people use this as a test to see if the gen is charging but not a recommended test. Doing this can cause the voltage to go very high and cause possible damage to other electrical components. Reverse field and armature connections ? why would you do that. You should have these identified from the start. No good guessing here but just follow the test that I described in the previous post. Regards, Kevin.