QuestionHOWARD:
THANKS---yours is an excellent answer so far to my situation; I really appreciated your answer ande it all makes sense. Now, let me clarify and add a few points:
I already had put my voltmeter on the generator; it is showing about 5 volts output at idle; this decreases to only about 2 volts when I accelerate. My dash ammeter shows discharge all the time, but shows increase in the discharge as I accelerate. The dash ammeter never shows a charging situation at any speed.
Importantly perhaps (?),I forgot to mention earlier that my battery is EIGHT volts, although the system is of course SIX volts, positive ground.
I can not get the battery to accept any charging no matter how I connect the charger to the battery---of course, it is a SIX volt charger being connected to an EIGHT volt battery.
Finally---the car starts and runs fine during all this! The fan belt on the gen seems fine. The generator and voltage regulator, as the rest of the car, appear correct/original. The car only has 50,000 miles on it.
Might I have a weak gen or voltage regulator? You had mentioned weak armature. If I replace the gen or volt reg, which to do first--or replace both?
Any new ideas? THANKS A MILLION.
==Ed
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Followup To
Question -
1940 Caddy LaSalle, positive ground system. As I accelerate, the discharge INcreases (reversed polarity?). How do I correct this---just reverse wires at the generator or ?
Also, when I try to charge my 8 volt battery, I get no amp reading from my battery charger no matter how I connect it to the battery.
THANKS in ADVANCE. ==Ed
Answer -
Hi Ed,
I am not a Caddy tech as you may see in my profile, however, I do know positive ground systems.
Don't reverse the wires on the generator.
First, you must get the tools necessary to do the job. You need a voltmeter (Radio Shack has them at a very low price). Volts are what you need to work with. Volts are the "Push" Amperage is the "Speed". You need to test the "Push" (Volts)that the generator produces.
First check to see if the generator belt is tight. A generator, when it tries to charge is a very heavy load and will make a belt slip and show a discharge when you rev an engine. Next check the battery voltage (on the "DC" scale) When you test the voltage you will also see which is (+) and which is (-). Your voltmeter will have a red lead for (+) and a black lead for (-). Also if the battery is not marked the two posts are a different size. The larger post is the positive (+) post.
If you reverse the wires on the generator you can do major damage so do NOT do that.
If you only have two wires on your generator, they should be a different size wires. The thinner wire is the "Field" wire and the thicker wire is the armature. Most generators can be made (+) or (-) ground without changing the wiring. It is done by "polarizing" the generator. If your system has been working correctly in the past and no one has done any work on the car, Than you should not need to "Polarize" the generator.
Put the voltmeter across the battery post (engine off) and read battery voltage. Have someone start the car while you watch the voltmeter. While the starter is engaged the voltage will drop by as much as 15% to 20% and as soon as the engine starts and is at idle you should see battery voltage or slightly over battery voltage. Have them raise the RPM up to a fast idle and watch the voltage, it should raise about 10% above battery voltage or a little more than battery voltage if it is operating correctly. If the belt is good and tight and you see the voltage drop to battery voltage or very slightly below that, then you may have either a worn set of battery brushes or a regulator problem. Also check all connections on the Generator, regulator, battery and ground strap to the frame from the engine and the ground from the battery to the frame.
If all this does not help you probably need to look in this "All Experts" under vintage or antique cars to get a tech on 40s cars.
No amp reading on a charger when you connect it to a battery can mean several things. Some battery chargers have a protection for reverse connection. Most battery chargers will show no amps if the battery is bad or completely dead or fully charged, so seeing no amps doesn't tell you much. Be very careful and look on the battery for a marking of (+)positive or (-)negative and connect the charger correctly. Red lead (+)positive and black lead (-)negative. If you are sure you have the charger connected correctly just leave it on charge for a good length of time. Than look to see if it shows any amperage on the charger ampmeter.
I hope this helps.
Howard
AnswerI checked with a friend who use to work on those old Cadys and he told me they were 6 volt systems and an 8 volt battery was available for hard starting problems.
IF your belt is tight (not seems ok) then you for sure have a charging system problem. Your 6 volt charger may not work on an 8 volt battery so if the battery is low you should get a 12 volt charger to charge it but don't leave it on charge long. Keep feeling the sides of the battery and see if it is getting warm. Also be careful and NEVER disconnect the charger cables while the charger is running. Two gases are produced while charging, Oxygen and Hydrogen. Keep in mind the Hindenburg.
You will need a charged battery to run the generator tests. You can't test the regulator until you run the generator tests.
Get two pieces of wire long enough to run from the generator to a battery connection or the battery itself.
Two wire generators either ground the field or hot wire the field to "Full Field" a generator. I could not get any info on your generator as to which it is. However, it is not important because you can't do harm if is done the wrong way.
First disconnect the two wires from the generator and place them so they don't make contact with each other or anything else. Connect your two test leads to the two posts on the generator and hold them so they do not contact each other or anything else. Place your volt meter across your battery so it reads battery voltage. Have someone start the engine and set it at a fast idle. Now touch the large post generator wire (Armature) to the hot battery post (-) then watch the voltmeter as you touch the smaller post wire (field) to the same post with the armature wire. (Now you have the engine at a fast idle and both wires are in contact with the (-) post of the battery. read the voltmeter. You should see the most that the generator can produce at that RPM. If you see more than battery voltage, have the RPM raised for a short burst and see how high the voltage will go. That gives you the max that the gen. can produce. If you got not voltage higher than battery voltage then move the field wire over to the ground (+) post and rev the engine again and read the voltmeter. If you don't get any high voltage reading either way, you have a bad generator. If one of the "Full Field" tests works than reconnect the car wires up,(small wire to the field and the larger wire to the armeture post. Than with the voltmeter still across the battery, start the engine and rev it up and read the voltage. If it is not higher than battery voltage, you either have a bad regulator or a wiring problem.
Let me know.
Howard
