Topic: Generator woes

[Chris]

Dearborn June 64, 260V8. My generator recently went out and I had it rebuilt by a local shop. I replaced the voltage regulator at the same time for good measure. My generator light is flashing red and not going out. I did the polarization technique for Ford generators, so that's not the issue.

I used a volt meter and measured voltage at the battery by putting the positve lead on positiove side of battery and negative lead on negative side of battery; it read 12.4 volts. I should be getting between 13 to 14 volts from the generator.

I'm not sure how to read voltage from the generator itself. I put the positive lead on the Field (F) terminal and the negative lead on the negative side of the battery and get 5.8 volts. Is this the right way to see what voltage the generator is producing?

[jwc66k]

Read the voltage across the battery with the engine off. If the not running and running voltages are the same, maybe running a bit lower, the generator may be bad. There was similar problem recently so use the search feature.
Jim

[Chris]

I checked voltage across the battery with the car off; it was 12.57 volts. With the car running voltage measured 12.3 volts, so something is wrong.

I need to know how to isolate the generator voltage in order to check its output. This is a Ford generator, the wiring to the 3 terminal voltage regulator is attached (B, F, and A terminals).

Most posts for this online are for a different type of generator. My generator has been rebuilt 3 weeks ago and I replaced the voltage regulator at the same time (repo from NPD). All wires look good and the harness is new.

[jwc66k]

If you have the old regulator, put it back and see what happens. Check with your generator's local rebuild company. They should have some level of responsibility. Then check with NPD, same level of responsibility. Most companies have a return or replacement policy, but it's short. If you're like me, you do things ahead of time and I get caught in a warrantee expiration trap.
Jim

[Chris]

I just put the old NPD regulator back in, hooked all connections except Field (and reconnected Negative terminal of battery), did the polarization step and then reconnected Field wire.

Checking the battery with the engine off shows 12.47 volts. With the engine running and warmed up shows 12.3 volts. Either I have two bad voltage regulators or something isn't right with the generator.

I'll be contacting the generator shop tomorrow. If I knew how to isolate the voltage output from the generator, I could see for myself if the generator is working properly.

[CW4macret]

When you say you " I did the polarization technique for Ford generators" do you mean you polarized the Generator and then the regulator?

[Chris]

No, not exactly. You typically polarize the generator through the voltgage regulator. For Ford generators, you unhook the NEG battery terminal, then on the voltgage regulator you unhook the white Field wire from the terminal. Next you "tap" the end of the white Field wire against the wire in the BAT terminal of the voltgage regulator (that comes in from the starter solonoid). You'll get a small spark. Now reconnect the Field wire in the voltage regulator and then the NEG battery cable. Ploarization complete.

You can do this at the generator by disconnecting the terminal leads on the generator and doing a jumper between the POS side of the battery and the "F" (field) terminal on the generator...get the spark and then reconnect all leads. 

[Chris]

I went through two AMK voltage regulators and at the third got it to charge the battery. There is a shunt in the voltage regulator that opens up and passes voltgage from the generator (coming in at the Armature terminal) to the battery (out the Batt terminal).

Here's the issue: the voltage off the generator is 15.57 volts and the voltage arriving at the battery (when running) is the same, 15.57 volts. The battery voltgage with the car turned off is 13.42 volts.

It seems like the voltgage regulator is allowing voltage to pass through but not regulating it down to the nominal ~14 volts and possibly overcharging the battery. The generator was rebulit with a brand new armature and brushes when I put the third voltgage regulator in. I have the dual pulley generator for A/C cars, so don't know if this is allowing a higher voltgage to come through to the battery.

[64rustang]

I had 2 reproduction regulators that did not work properly on my May '64 I6.   I had wild voltage fluctuations.  I found an NORS Autolite unit on eBay that works perfectly.  I did have to clean to contacts, even though the canister it was in had never been opened.  I also swapped the covers.  I would suggest trying to find a NOS or NORS regulator.  Another benefit of a NOS or NORS regulator is you can install the plastic terminal cover on the regulator.  They do not fit on the repro units.