VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Generator Problem

Went out first thing this afternoon and was going to look into what I thought was s starter dragging.

Battery was dead. As in plum dead. Wouldn't turn the engine as in defiance.

Took the jumper to it. 12 volts. Spun the engine like an old timey windmill in Oklahoma.

Decided it wasn't the starter. Must be the generator. Engine would die like a cockroach on a exploding "A" bomb. (well.that's about the only thing that will kill them)

Took the generator off. Took it apart. Brushes looked new, commentator looked a little dark, cleaned it with 100 grit sandpaper. Put it back together,

Put the generator back on the car.  Polarized it.

Cranked it up. No charge on the amp meter again.

Took the voltage regulator off. Cleaned the terminals and the contacts. Put it back on. Same da..ed thing. No charge.

Took the generator off and got another one. Almost new looking inside. Cleaned it up anyway. Back together. Put the jumper cable to it. It slowly spun. Figured it was OK and that I was on the right path.

Put this generator on. Polarized it. No difference.

Got a NOS voltage regulator I had hide back for harder times. Put it on. Polarized it. Charged but in the wrong direction. As I would rev the engine it would increase toward discharge on the amp meter.

Polarized the voltage regulator again. Now the needle is in the center as it was to start with. No charge.

Any ideas? Yes, I have considered selling it, putting a 45 round through the block, making it into a rat-rod and even installing an outside shade thing on it. I think I'll just beat the missus to get relieve the frustration. (I actually won't even consider the last thing there. Among other considerations, I don't think I could win.

I could use some help here guys. I'm at the end of what's left of my wits and ready to pull the rest of my old grey hair out. Am too!

Best,

Charlie

BTW: It is the grey car.

At least this is keeping you young at heart as this would be a full days work for even a youthful mechanic.

How do your ground cable connections look? All cable connections involved with this?
A really defective battery? Maybe charge battery overnight and load test it in the morning with headlights and a volt meter.

I would remove the cover on the volt.reg. and make sure none of the contact points welded together due to the current going the wrong way.

Hi Charlie,

Yes, electrical problems are the ultimate test no matter what year or make of vehicle.

One simple test is to determine how the system reacts when you turn on the headlights. You probably have done this. With the engine not running does it show a discharge? What happens when you turn them on with the engine running?

Gene and Tim are heading you in the right direction. The key is to determine if the problem is the generator, regulator, battery, or wiring.

Thank goodness I have access to a traditional electrical shop both here in Scottsdale and in Davenport. I would take both of the generators and have the shop test them. They might even be able to test the voltage regulators.

I agree with Tim that a truly bad battery will not accept any type of charge. What happens when you connect a charger to it?

Rusty the battery charges up with my battery charger.

I should be smart enough to figure this out without goiing the professional route with their stinkin' testing equipment. This here right here is not rocket science.

I have a generator that I know is working on the 41 coupe one I just took off the 1950. I'll check them out on it and see what happens.

Wish me luck,

Thanks,

Charlie

A simple test if you have the generator off is to see if it will motor. Use jumper cables ground to the case then use a jumper wire to ground the field terminal, then touch the positive cable to the armature post. The generator should the run if it’s good.

I agree that they should all run when doing this test. They all do.

I have now put on yet another generator off the 50. It toos spun like crazy.

Cranked up the 41 coupe. It charged just like it should.

Took the voltage regulator off it and put it on the grey car. Nothing changed. Same problem.

Next I will take the generator off the coupe and try that. I don't expect any different outcome.

The battery is good, the cables are good and it will start up without assistance from a jumper even thought the battery is drained down to almost nothing.

Thanks for your input. All advice is welcome. I admit I am plum baffled.

Best,

Charlie

Well, If you tried both the regulator and the generator off a known working system, then I guess you know its the wiring.

http://chevy.oldcarmanualproject.com/shop/1941/41csm260.htm

Looks like about 4 wires to check, plus the grounds. Are you sure the body, frame, and engine/trans are all grounded together? Could you have lost a ground strap somewhere?

Did the ammeter ever do what it should on this car? Maybe someone in the past hooked the ammeter up backwards?

I would suggest that you stop changing so many parts in and out! I would start with the original combination. Start the motor, bring the idle up some, put a voltmeter between the generator terminal and ground and then momentarily ground the field, at the generator. If the generator is good, the voltage will go up. If that works, try grounding the field at the regulator. If that doesn't work, the harness between the generator and the regulator has a problem.

It was all working properly until last Saturday,

All grounds are good.

But something is surely wrong. I'll tackle it again Monday.

Thanks,

Charlie

Been thinking. I think I have a wire problem in the loom to the voltage regulator. Tomorrow I'm going to see if there is continuity from the end of the gen and field wires to the voltage regulator.

I think that after all this swapping parts there may be a problem with a wire.

We'll see and I'll keep you posted.

Best,

Charlie

Hang in there Charlie, you will figure it out, I have faith in you!

Thanks Unclle Ed,

I checked for continuity but not that. All wires were good.

i'll do some more thinking and tinkering.

Best,

Charlie

If you haven't done so yet:

1) Charge battery fully 100% with a charger
2) Disconnect charger
3) Measure battery voltage immediately
4) Turn on the headlights and measure the voltage with the headlights on
5) Compare measurement in 4 to measurement in 3. Voltage should only drop a little and should be very close to 6v with lights on. If under 6v battery is suspect.

If you have a battery load tester and know how to use it, then obviously use it instead.
I have seen bad batteries where chargers "think" they are ok, but as soon as you put a load on them, the voltage drops off to almost nothing and they cause really bizarre electrical problems.

Charlie, your comments about the wire reminded me of a story from work (Moderator, this is related to the thread).

I was working for IBM as a mechanic for some of their production lines. One machine, a VERY high-end computer-controlled lathe would stop mid cycle and 3 shifts of mechanics could not figure it out. I finally took my turn at it. The Lead mechanic showed me how the machine would go through its movement and just stop mid way. Like the over run limit switch had been hit. But the switch actuator was 6 inches away.

Now, I noticed that small bundle of wires that drooped between the limit switch and it's actuator. Hmmm. I opened up where the wires connected to the limit switch. I pulled gently on all the wires and one of them came out of the insulated sheath. As the wire loop moved up and down with each cycle of the machine, the wires, even though there was a large loop, bent back and forth and over time one wire broke. The broken ends made electrical connection when the lathe as in the home position, but after it moved a little (and the drooping wires made the broken wire to come apart), the disconnect acted like the limit switch and shut off the lathe.

I know, a long harrang to agree that there might be a short in the wire harness. While checking the continuity, gently pull on the wire and see if the wire disconnects the circuit. If so, you might have found your short!

Cheers, Dean

Well, I didn't actually pull on the wires when they were loose and checking for continuity. I'll do it again and see what I can find.

Thanks,

Charlie

The type failure that Dean describes is very common in the wiring harnesses that connect between the body and the doors and trunk lid in a modern car. Sometimes the failure is a short where the insulation gets worn. Most of the time the conductor in the wire breaks in a fatigue type failure due to the repeated movement.

The failure is tough to find and hard to repair because there is no extra wire length in the harness. I often have to insert a short piece of wire and create 2 soldered splices to get things to work electrically and allow enough movement.

Don't forget to put the heat shrink wrap on before you solder the second joint!

Today I just sat on my butt and thought "what in the world could this be causing the gen not to charge. No revelation. Devine or otherwise.

Tomorrow I going to pull on the wires as I check continuity once again.

It was too cold and windy here today to work outside. Sunny but the temperature only got into the low 60s with a breeze blowing. Who can fault me for not going out there in such severe wintery conditions? Mercy!

Maybe tomorrow it will warm up a bit so the a civilized person can venture out into the elements. I might as well be over in Asheville and snuggle up with the grizzly ol' Chip.

Stay tuned. I'll keep you posted.

Best,

Charlie

Gee Charlie,
It got up into the high 50s here today and I worked outside a bit and had to take my jacket off! I was thinking about getting the hose out and washing the car.
PS. Good luck with the generator, you will figure it out when the weather warms up!

Warning this is long and a little embarrassing. I advise you to not read it. it ain't worth it. If you do then don't yell at me. You've been warned.


Well,

Today I finally figured it out. Consider this:

The generator was bad. After I took it off and cleaned it up and put it back on it still was bad.

Thinking the generator was good, nest I got out my voltage regulator and tried two I had (one NOS 301. No joy.

Took Voltage Regulator off 41 coupe. It showed a charge at amp meter. No joy when installed on grey car.

Took Generator off 41 coupe. Amp meter showed it was charging.

Put 41 coupe generator on grey car. I knew they would work. No joy.

Got maintenance manual down and reviewed generator part. Wording and diagram looked as if I had the field and arm wires basacards. Strangely, I had switched their positions on the generators.

Switched Generator (ARM) wire to lower post and field wire to upper post. Charged! Did cartwheels.

Put new Gerator and Voltage regualtor on and made sure I got the wires hooked up correctly.


(I know this here right here is plum boring but bear with me.if you can stand it)


Missus called me in for dinner (supper), I asked what we were having and she said " Last week's ripe Road Kill. It's getting a little rank and we.need to eat it soon or throw it out and if you don't like it, go out and shoot something fresher. My thrifty hero." (Well, roadkill is like manna from heaven and helps with savings I can buy something else for the 41s.)

She asked if I had fixed the car? I replied, "Of course. What do you think I am, an idiot?'

She asked if Gene, Chipper, Bob, or Chip and any of rest of you guys on Chat had been of help to me. I replied that all of you were worthless when it came to really technical stuff. She rolled her eyes and said, 'Oh, you da man alright." (seemed laced with doubt0

I said that one thing was for sure and she asked, Now what would that be, Mr. Goodwrench man." I said that, "From now on I was going to review the maintenance manual before I tackled such a complicated repair job.

At that she dipped something unidentifiable out of the steaming pot on the range and flopped it on my plate, she mumbled the famous John Wayne line, "That'll be the day."


Sorry to bore you so much. I could have sworn that I had the wired right all along. Not. All together I think I took the voltage regulators off and on and the generators out and in at least ten times each. It's hard being stupid. Is too

Best,

Charlie

BTW: There was a heap of continuity checking and tracing wires, going under the dash, etc involved also.

BTW2: It was cold out there (low sixties) and I liked to have froze my behind off. Did too!

Glad you got it fixed!

Sorry for a late reply Charlie, i find the nos regulators have dirty contacts from shelf life. The cutout contacts are soft so go easy there. The current and voltage regulator contacts are a harder material so i use carborundum paper. I remove the field wire from the gen and measure the resistance to earth of the regulator field circuit. This should be zero ohms. If it is not either the voltage regulator contact or current regulator contact is dirty and the gen wont charge. Saves taking the gen out to check for the fault.

Thanks,

I'll remember your advice.

Best,

Charlie