How to test discharging generator
 

Went for a cruise in the '61 and the ammeter gauge suddenly showed a discharge. I put a voltmeter on the few month old battery and the car was running off the battery at a little over 12 volts. No voltage change or charge when raising the RPM'S. How do I isolate the generator from voltage regulator as the culprit? Battery is good and holds a load test. Thanks

I don't know how the 61 is set up but the same thing happened to me last year in my 59..... it was the voltage regulator for sure... my generator has never failed and it is 53 years old... I think I replaced the brushes once back in the 70's...

Forum members 1snake and buns each provided detailed testing procedures on this a few years ago. If you are unable to find their posts, I will look them up when I return home.

+1 ....the regulator may need adjusting, they have 2 or 3 sets of points, that arc up over time,,, if you want to fix it yourself, check out teh procedure in an old motors or chilton manual,,, its not hard to fix, if thats the problem....or, in todays world,,, just replace it!!!

the generator will need brushes replaced periodically, but it is pretty bullet proof,, bearings go out if its been sitting a while or not lubed ...

i like teh old repair manuals for working on these old cars, its how they did it in the day....

Thanks Jeff, Could not find any definitive tests in the ST-12 or '61 pass manual. Where is the best place to get a regulator?

Grounded the regulator field to the regulator case and no change in voltage. Jumped the generator regulator terminal to the regulator batt terminal and just a very very slight drop page in voltage.

Bob, Where did you get the regulator and does it have to be polarized?

Any parts store should have the regulator, they are about $30.
If yours is the original, you can have it rebuilt, John Pirkle restorations does them. http://www.johnpirkle.com/
John passed away, but apparently his son is continuing the business.

:cheers:

Paul

From ZIP Cporvette... # es-490... was about $28... just slapped it in and away I went...

NAPA had the same one but was alittle more....

Here are the contents of a file I created based on information from this forum:.

Polarizing Regulator
Correct - with the engine off, use a U-shaped insulated wire and touch it briefly to the "Bat" and "Gen" terminals at the same time; you'll get a juicy spark, and you're done
http://forums.corvetteforum.com/1566729014-post14.html

Testing Generator #1

1. assuming the wiring is all good including grounds etc.
2. get a voltmeter and connect it to the battery.
3. remove the Blue field wire 'F' from the generator.
4. start engine. run at about 1200 - 1800 rpm.
5. with another test jumper wire connected to the 'F' termial on the generator;
6. momentarily connect the test jumper to engine ground (block or head etc.)
7. watch the voltmeter.
8. if the voltage goes up to 13 to 18 or so volts; the regulator is the likely problem.

http://forums.corvetteforum.com/1566714417-post2.html

Testing Generator #2

1. The easiest and best way to check output AND rule out the volt. reg. is to disconnect all the wires from the generator
2. hook a volt meter to the arm. terminal (brown wire) and start the car. You should have between 2-6 volts.
3. Now ground the field terminal (blue wire) and you should get over 15 volts when you rev. the engine.
4. If you do, you have a bad regulator (assuming your wiring is okay). If you don't, you have a bad generator. Simple as that.

http://forums.corvetteforum.com/c1-a...r-problem.html

Thanks Jeff! I hadn't seen that one. :thumbs:

Dump that POS mechanical regulator and go solid state...there is only ONE source for this conversion in a generator car: http://www.wiltonae.com/home/index.aspx

I was maybe the first person to do this conversion on a C1 (according to the owner of Wilton Electric) 4 years back and haven't touched it since. Even bought a spare conversion just in case (haven't needed it yet). Totally invisible swap too.

Get prepared for the naysayers that will tell you their mechanical V/R from the Jurassic epoch has never failed in two hundred years. I wonder why some people on here even have tool boxes as everything on their car lasts indefinitely.

Here is a quick way to check the generator (in or out of the car):
• Disconnect all wires from the generator
• Disconnect the fan belt
• Ground the field terminal to the generator frame
• Connect the armature terminal to the battery +12V*
• Connect the battery -12V terminal to the generator frame

The generator should now start running as a motor and turn at approximately 1000RPM

* If you connect an ammeter between the armature terminal and battery you should read approximately 4.7 to 5.6 AMP.

Pierre