voltage regulator

[Howard H.]

Can you check voltage regulator output by checking voltage with multimeter at the battery terminal of the regulator and negative post on battery with the motor running? This on a 58. Am trying to get bugs worked out after installing rebuilt motor, original generator and regulator. Gauge says generator not charging. Had it checked and is working properly. Regulator is a 58 rebuilt by John Pirkle so I am assuming it is ok. It has been sitting on the shelf in a box since he rebuilt it. Am looking for suggestions on what to check. Wiring harness not changed old generator and voltage regulator worked fine according to the gauge. any suggestions would be appreciated.
Howard Hiller

[Dan D.]

Re: voltage regulator

Howard, did you re-polarize the regulator after you installed everything? You have to momentarily short the batt. terminal on the regulator to the (A) armature terminal. A spark will be normal, but this will get the current going in the right direction. This is usually required if everything has been apart for a period of time, which you say it has.

One other quick check you can do is ground the field terminal (F) on the generator - with the motor running. Do NOT ground the armature terminal. This causes the generator to put out full current and your battery voltage should rise. Keep in mind you have to rev the engine to 1200 - 1400 RPMs to get these old generators to put out enough voltage for the regulator to start charging. Generator voltage has to be higher than the battery voltage.

Measure the battery voltage right at the battery. If charging it should be above 12.6 volts and slowly rise to around 14 volts when the battery reaches full charge. Can be as high as 14.4 volts, but no higher as this will cook the battery.

-Dan-

[Frank D.]

Re: voltage regulator

Howard, did you re-polarize the regulator after you installed everything? You have to momentarily short the batt. terminal on the regulator to the (A) armature terminal. A spark will be normal, but this will get the current going in the right direction. This is usually required if everything has been apart for a period of time, which you say it has.

One other quick check you can do is ground the field terminal (F) on the generator - with the motor running. Do NOT ground the armature terminal. This causes the generator to put out full current and your battery voltage should rise. Keep in mind you have to rev the engine to 1200 - 1400 RPMs to get these old generators to put out enough voltage for the regulator to start charging. Generator voltage has to be higher than the battery voltage.

Measure the battery voltage right at the battery. If charging it should be above 12.6 volts and slowly rise to around 14 volts when the battery reaches full charge. Can be as high as 14.4 volts, but no higher as this will cook the battery.

-Dan-

I think you'll find generators are polarized, not voltage regulators...

[Dan D.]

Re: voltage regulator

Connecting the battery positive terminal to the armature terminal of the generator momentarily passes current through the generator's armature. and establishing a positive charge on it. So yes, you are polarizing the generator.

-Dan-

[Howard H.]

Re: voltage regulator

Thanks Dan
I did polarize the generator after I got everything back together. I will try grounding the field terminal to the generator. The battery is new and I have it on a maintainer so it is fully charged. When I turn the headlights on the gauge shows discharge with the motor running. Maybe I need run rpm's up to 1500 or so to see if it will start charging. I polarized it by touching the battery terminal and the armature terminal. Got the spark. Is that any different than your follow up by touching the positive battery post and the armature terminal on the generator?

[Wayne L.]

Re: voltage regulator

IIRC, some of the AIM wiring diagrams show the ammeter connections reversed. Try swapping the two main connections at the ammeter.
FWIW, Wayne

[Howard H.]

Re: voltage regulator

Thanks Wayne
The gauge worked correctly with the old generator and voltage regulator installed.
Howard

[Dan D.]

Re: voltage regulator

Sounds like you did it right Howard. And you got a spark. That means it needed to be polarized. Try running the RPMs up. You need to do this.

If you ground the field and it charges, that means the generator is working and you need to head to the regulator. You can pull the lid on the regulator and touch the relays - to make sure they aren't stuck. If you have old wiring, make sure the wires aren't broken at the terminals. If the wiring is old and the terminals are moved around, like when re-installing everything, they can break under the insulation right at the terminal and you will not see it. I have been burned by this in the past.

-Dan-

[James O.]

Re: voltage regulator

yes to what everyone said above but also try this. there is a terminal ring with a small steel braid around the wire that attaches to the cover of the voltage regulator. the other end connects to the generator. i am not near my car but i think it is for a ground between the 2 components. as a test, connect a solid wire like a jumper cable from that same bolt on the regulator that bolts to the inner fender (making sure that bolt has metal to metal contact with the VR base) and the other end of the jumper cable to a solid bolt on the car chassis. there is one close by near the front of the frame. then after you start car watch your ammeter and check voltage right at the battery and i 'll bet you will see the 14 volts at the battery. if that works, there is a cheap fix. jim o.

[Howard H.]

Re: voltage regulator

After having no luck getting the generator to charge I took the generator and voltage regulator to the shop to be checked. The same shop I took the Generator initially. The said the regulator wasn't working. So I stopped by the NAPA store and picked up a new one. Put it back together, polarized it and started it. The gauge showed it to be charging for a few seconds and then stopped. Turned the motor off and started it again and again it showed it was charging but quit after a few seconds. Nothing after that. Apparently I have something that is killing the voltage regulators. The only other things I changed when I installed the motor was the starter, solenoid and the ballast resistor. I have a good wiring diagram ordered. Not sure what to check now. Suggestion appreciated.
Thanks Jim. I hooked a jumper wire from the braided terminal on the voltage regulator to the braided ground on the right motor mount and didn't see any change.

[Jim L.]

Re: voltage regulator

The gauge showed it to be charging for a few seconds and then stopped. Turned the motor off and started it again and again it showed it was charging but quit after a few seconds. Nothing after that.

What you've described is correct behavior.

The generator/regulator will charge only long enough to replenish the energy removed from the battery by starting the engine. Once the battery is again "full" there is no need for additional charging.

[Frank D.]

Re: voltage regulator

What you've described is correct behavior.

The generator/regulator will charge only long enough to replenish the energy removed from the battery by starting the engine. Once the battery is again "full" there is no need for additional charging.

Jim has it right - what you are describing is perfectly normal operating characteristics....
The system is not in a constant state of heavy charging, once things are stabilized a reading at or near zero is acceptable.
Here is my 61 (with Tremec OD) tooling along at interstate speeds with its original generator which I never touched in 10 years of ownership.

[Howard H.]

Re: voltage regulator

Thanks Jim and Frank;
What concerns me is the gauge shows slight discharge at idle and when I turn the headlights on it shows more discharge. I thought the regulator should kick in and bring the needle back to center.

[Jim L.]

Re: voltage regulator

Thanks Jim and Frank;
What concerns me is the gauge shows slight discharge at idle and when I turn the headlights on it shows more discharge. I thought the regulator should kick in and bring the needle back to center.

That, too, is perfectly normal with a generator system. The engine RPM has to be off-idle before the generator output is sufficient to power the car electrics. The exact RPM at which the generator will take over from the battery varies with pulley diameter and the adjustment of the Voltage regulator.

[Frank D.]

Re: voltage regulator

Yes again, maybe the OP is used to alternator systems where one advantage is low RPM charging....
To wit, normal behavior once again..