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DSpringer

Generator Emergency

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Returning from GOF West in Montana to California I noticed the ammeter jumping around a lot. Just before reaching Salmon, ID we started smelling something burning and the ammeter needle went to neutral - in other words no generation. The generator felt hotter than usual, like the field coil had overheated.

 

Is it possible for a bad voltage regulator to take out the field coil? I had trouble with one of the brushes before and will check that in the morning, but I'm concerned the generator is fried. Have too far to go on battery, and need to drive at night to avoid the 110 deg. CA heat.

 

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A bad regulator can take out the generator. It sound like your generator armature needs to be rebuilt. Look in your Club roster for someone near your current location that may have a spare or knows who can rebuild your generator

 

Another option is to buy a spare Optima battery or 2 and charger. Disconnect and insulate the generator wiring and drive on the battery. When one battery is discharged, swap to the spare. When you stop, recharge both batteries. Don't let the batteries completely discharge, the current chargers won't recognize a completely discharged battery.  My guess is about 3 hours of night driving with only the lights on a good Optima. Maybe someone else has a better estimate. The cost of the batteries and charger is much less than a flatbed.

 

Edit: I just checked the Optima site and it says that you have 100 minutes of drive time with a 25 amp draw. So if you unplugged the passenger side headlight you would be just over the 25 amp draw and could get an hour of drive time on a fresh battery. It would be much better to lay over and have it repaired or rent a U-Haul to take it home.

Edited by 19tom40
update (see edit history)

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We replaced the regulator with a brand new one from Napa and still fried a rebuilt generator - so that makes three we burnt up on the return trip. We dropped one of the generators off at Auto & Truck Electric in Sparks, NV on Wednesday. Bob, the owner, called this morning to say he had already re-wound the armature and it was ready to pick up. He also told us that Optima's can be death on generators because their charge rate exceeds the capacity of the generator. I'm sending him a couple of voltage regulators to see if they might have been the problem. Apparently they can install alternators inside the generator casing. I'm thinking hard about that. 

 

If you're ever in Salmon, Idaho you must visit Lee at the wrecking yard on South Cherokee Road. The most amazing collection of antique autos I've ever seen. And the best stories! All the adversity we experienced put us in touch with people who are incredibly kind and helpful.

 

We could have made it home from Fernley, Nevada on the new battery we bought, but probably couldn't have gotten over Donner Summit in the 98 deg. temperatures and might have died in the 112 deg. heat in the valley if we had. With help from our friends we trailered her the rest of the way home from Reno.

 

We REALLY enjoyed GOF in the Bitterroot. That, plentiful trout from the Big Hole, and he kindness of strangers made the trip worth it.

Edited by DSpringer
Forgot to include some stuff (see edit history)

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45 minutes ago, DSpringer said:

He also told us that Optima's can be death on generators because their charge rate exceeds the capacity of the generator

Huh?  Can you explain?  If your generator puts out 20A vs 35A in another car, the lower charge rate means it takes longer to recharge the battery.   How does the battery burn up the generator?

 

The fleet in my signature use 6V Optimas with a variety of charging rates, and I've never fried an Optima or a generator while an Optima was installed.

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DSpringer, You may have a grounding problem. If the generator and regulator do not have the same ground potential, your generator can go unregulated. There are 2 ways to make sure that the ground is the same. Best way is to use a wire between the case of the generator and the mounting screw for the regulator. The Ford harness had that wire in it for a couple of years around 1942. The generator had a 3rd bolt for the ground.

 

The method that I use is to install an internal toothed washer behind the regulator mounting bolt and scrape some paint at the generator mounting. Make sure that the grounding strap from the battery to the body and the strap from the body to the engine are in good shape. If they are more than 10 years old, I would replace them.

 

When you have your generator and regulator installed, connect your voltmeter to the BATT terminal of the regulator and check the voltage as the RPMs are raised. The voltage should not go above 7.6 Volts and should be 7.2 - 7.4 Volts with the regulator at operating temperature. It takes about 5 minutes of running to get the regulator up to temperature. If your grounds are good and you exceed the voltage, the regulator is bad or incorrect for your car.

 

When you install a regulator or generator, make sure that you have the battery disconnected. A spark can cause damage.

 

The guy in Sparks that told you that a battery can cause a generator to go, is full of the same stuff that came out of your generator when it went. The voltage regulator controls the amperage and voltage from the generator. A bad regulator or a poor grounding are the most likely causes of frying a generator.

 

Alternators also have problems in the slow turning engines in our collector cars. Sometimes they will not rotate fast enough to self energize and they seem to blow the diodes faster in the older cars. They also need more belt contact than a generator. The main advantages of an alternator is the higher output and less maintenance.

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I have known Bob at auto and truck for over 35 years,he is the best you can find for elect problems.I have a 1941 lincoln custom with the limo option.I am using an optima battery and the 75 amp alt in a gen case from speed way auto.the alt has a built in regulator.i have the old regulator on the fire wall gutted and the wiring pass thrue so it looks like i have all of the original electics   The problem with an optima battery with a generator is the optima will accept as much charge as is available.the gen with a reg will try to charge but cant keep up with what the battery will accept and kills it's self trying. The optima with an alt and built in regulaor works well. my custom has elect over hyd windows and i have installed an elect cooling fan in front of the radiator.I can do stop and go traffic at 95 deg with the head lights on and not run down the battery.

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I run a slightly taller marine version of the oem 2f 6 volt lead acid battery. The generator is grounded through the case, engine ground only..regulator set at 7.6 or so and 

I dont have any real trouble--I have clean recent ground cable to block and body, ( batt tray) I have discovered that good very clean , very tight connections on correct gauge cables

have done the trick for me, lights are a little dim at idle with radio on, but I have realized about 5 years for a battery, I replace it before it fails..start engine  or low amp charge

over the winter. Car is in attatched  unheated garage.  

I do find the lack of acid in these new battery's attractive, have not taken the plunge, I'd like the one that says LZ on the side!

I am glad DSpringer made it back safe!!   Cant rest till that car is back at home base, in garage secured!!  

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Antique Auto Battery has the Zephyr script batteries, with the Optima battery inside.   Enourmus cranking ability. I painted the script,with gold sign painters paint.

 

Tom

 

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Edited by Tom_Overfield (see edit history)

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I have been using an Optima with a generator and voltage regulator since 1998 and have had no problems.

 

An Optima is charged like any other lead cell battery. It will not ever destroy a voltage regulator or generator. If what Tom Nelson says about charging an Optima were true, it also would be true of a conventional battery that had shorted a shorted cell. The purpose of the regulator is to regulate the voltage and current that the generator supplies. The Optima is just a lead acid battery with the plates wound in a circular manner and sealed in a case. If you need more info on Optima Batteries, go to their web site.

 

I have been driving and maintaining cars for almost 70 years and have had numerous batteries with shorted cells and non of them has fried a generator or voltage regulator. During the time I have fried 2 generators, one because the regulator point stuck and did not regulate the voltage going to the battery and the other because I did not know enough to adjust the 3rd brush properly.

 

DSpringer may have a grounding problem or he may have failed to polarize the generator when he installed it. He did not mention the ammeter moving in the discharge area, so I did not consider the polarization of the generator. To do this on Ford products, remove the wire from the Field terminal and touch it to the BAT terminal for a second.

 

If you ever buy a script battery, when it eventually dies, save the case, so you can save money by installing a new Optima in the case.

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Thanks, Toms. The explanation Tom N. provided matches what Bob said and makes sense.  Before the second generator fried the ammeter was showing a high rate of charge, but the third one (with the new voltage regulator) showed only a moderate charge. The generators were so hot that when we poured water on them they steamed. What's really baffling is that we had no problems driving the 900 miles to Hamilton. It was only on the return trip that we started having issues. We did polarize the generators after they were installed by jumpering briefly between field and battery. 

 

The wiring diagram for the 41 shows a wire connecting the case of the voltage regulator to the case of the generator. I verified that the grounding wire, which is in the harness, is in place at that there are zero ohms of resistance between the voltage regulator case and the generator. There is no third brush. Next step is to send the regulators to Bob to check out. 

 

This car was owned by our grandmother (she died in 1967 at 89). She has been blamed for certain strange occurrences, such as scaring undesirable tenants out of the old family cabin. In Nevada we were caught in a tremendous thunderstorm and the windshield wipers acted like the vacuum hose was disconnected. Back at the hotel I checked the vacuum lines and they were all connected and the wipers worked just fine. Go figure.

2nd voltage regulator.jpg

3rd generator.jpg

Edited by DSpringer
Didn't see earlier postings, added pictures. (see edit history)

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           Here is a link to an article explaining how a voltage regulator works.

 

http://www.secondchancegarage.com/public/83.cfm

 

I read Tom Nelson's explanation and it makes no sense whatever. If what he said was true, most of us would have burned out several generators with our Optima batteries. The voltage regulators work the same way, whether they are designed to work with an alternator or generator. All lead acid batteries will accept all of the charging current an alternator or generator can provide, it is up to the voltage regulator to limit the output of the generator or alternator to prevent the destruction of the

 

If the voltage regulator relay failed to pick, the field would be tied to ground and that would destroy the generator. The regulator needs a good ground to pick the voltage regulator relay at the correct time. The same conditions are needed for the current regulator relay. The extra wire added to the harness, provided that ground. If the field and ground wires were reversed at the generator, that would also ground the field causing the generator to destruct.

 

It sounds like you may have had a couple of bad regulators or generators or a combination of them.

 

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Possibly part of the problem here could be due to constant running,  900 miles  each way  prolonged running on 70 year old  windings., heat build up breaking down old insulation, creating a high current short circuit.     

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The diagnosis Bob at  Auto & Truck Electric gave me was that it was a combination of current draw from our 6V-12V converter and the high temperatures. The age of the generators no doubt contributed. The two voltage regulators we were using were only slightly out of calibration. We will think twice before making long trips in high temperatures, as much for our comfort as for the welfare of the car.

 

Thanks for all of your input.

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