Charging System Question

[rustydog]

On my B..have 12v neg grnd generator, voltage reg, all new guages....gen & reg new as well. When not running..with light switch on ampmeter shows SLIGHT drain.

When started and running, even at high rpms..got nothing showing on ammeter.. Does this ring any bells to the electrical masterminds out there? Could I have neglected to ground something somewhere?? any ideas at all would be most appreciated....any simple tests to isolate problem?? thanks fellas

[gearhead204]

does your voltage regulator require "polarizing" I can remember older equipment requiring this before system charges.

[Randy mckinney]

Some volt reg need good ground. I had one bolted to fire wall and we painted truck and it woulnt charge scraped some paint back were reg bolts on an problem fixed. Just a thought.

[41chevy]

Here are the procedures for both types of systems, from the U.S.Military manual

POLARIZING THE ELECTRICAL SYSTEM

Whenever a generator or a generator regulator is tested, repaired, or replaced, the generator must be polarized. If this is not done, the generator may be damaged and the regulator contacts burned. Reversed polarity will discharge the battery - or damage it.

There are two types of generator and electromechanical voltage regulator combinations used with DC generators.

In an "A Circuit" system, the field is grounded through the regulator. "A Circuit" systems are found in most Ford and GM vehicles.

Most Chrysler vehicles had a "B Circuit" system which was grounded internally through the generator.

To polarize an "A Circuit" system, connect the FIELD, ARMATURE, and BATTERY leads to the regulator. Connect the battery. Then, momentarily connect a jumper wire between the ARMATURE terminal and the BATTERY terminal at the regulator.

To polarize a "B Circuit" system, connect the FIELD, and ARMATURE leads to the regulator. Connect the battery. Then, just before installing the BATTERY lead, momentarily touch it to the ARMATURE lead terminal.

Milatary model MACKS have electrical systems with the POSITIVE battery terminal grounded.

TM 9-810, 5 and 7 ton cargo truck / MACK / REO,U.S. War Department 1955

[ThomasGardner]

Rustdog,

I just went thru the same thing with my '58 H63. I changes the electrical system from positive ground to negative ground. I first found a local auto electric shop had the generator & voltage regulator checked out. Found the two end plates mounting hole were out of round and armature had flat spot. luckly they had end plates and armature from another generator. The voltage regulator was sticking, they got me a new one (50amp) with double contacts (came with voltage regulator installation instructions), shows polarization instructions. I also attached series/parallel swith instrcution that show voltage regulator connections. Hope this helps.

Tom

[rustydog]

Thanks for all the replies.......unfortunately, I still havent figured this out yet.....seems everything is connected correctly, polarization is also correct, checked grounding as mentioned in thread. The engine was not grounded, so I am going to do that...dont know if that is problem, but suspect maybe...stay tuned

[41chevy]

Thanks for all the replies.......unfortunately, I still havent figured this out yet.....seems everything is connected correctly, polarization is also correct, checked grounding as mentioned in thread. The engine was not grounded, so I am going to do that...dont know if that is problem, but suspect maybe...stay tuned

If you have a voltmeter, here are some easy tests to make:

Measure the voltage across the battery. Should be about 12 to 12.6 volts with the engine off. As the engine speeds up, the voltage should increase to somewhere around 14 volts. If it does, the generator is working and charging the battery

Did you polarize the generator with the belt off. If you had the belt off and it did not spin, the generator my be defective. Automotive /truck generators need some magnetism to get started. This "residual" magnetism remains in the Field pole pieces even after the engine has stopped.

You might also pull the cover off the voltage regulator and make sure the points are not fried shut after running it. Even though the Regulator was new it only takes a second to burn the points. Most of the OEM style have a screw on cover to "tune it"

[gearhead204]

yes get your grounds installed!!!! this will cause all sorts of mysterious problems, eng. needs to be gnd. to frame, frame needs to be grounded to the body, if in doubt add a ground to many are just enough.

also you can test the gen. on the truck un hook the wires and drop the belt. I looked on line but cant find the directions if I remeber right you gnd the frame and power the field. and armature should spin. this will tell you if generator is functioning properly.

IF ANY ONE ELSE KNOWS THIS TEST PLEASE CHIME IN

[41chevy]

yes get your grounds installed!!!! this will cause all sorts of mysterious problems, eng. needs to be gnd. to frame, frame needs to be grounded to the body, if in doubt add a ground to many are just enough.

also you can test the gen. on the truck un hook the wires and drop the belt. I looked on line but cant find the directions if I remeber right you gnd the frame and power the field. and armature should spin. this will tell you if generator is functioning properly.

IF ANY ONE ELSE KNOWS THIS TEST PLEASE CHIME IN

The diagram is for a neg ground system , same for positive ground just different battery terminals

Disconnect the generator from the regulator (probably easiest to simply take the wires off the generator).

Connect a jumper from DF on the generator to the generator frame. Now run the engine and measure the voltage from ground to D+ on the generator.

NOTE: Some generators have different types of terminals;

verify which is DF and which is D+.

As you increase the engine speed, the voltage should jump up to +25 volts or so

If it passes this test, the generator is good.

(Don't run this test longer than necessary as it will overheat the generator.)

[rustydog]

If you have a voltmeter, here are some easy tests to make:

Measure the voltage across the battery. Should be about 12 to 12.6 volts with the engine off. As the engine speeds up, the voltage should increase to somewhere around 14 volts. If it does, the generator is working and charging the battery

Did you polarize the generator with the belt off. If you had the belt off and it did not spin, the generator my be defective. Automotive /truck generators need some magnetism to get started. This "residual" magnetism remains in the Field pole pieces even after the engine has stopped.

You might also pull the cover off the voltage regulator and make sure the points are not fried shut after running it. Even though the Regulator was new it only takes a second to burn the points. Most of the OEM style have a screw on cover to "tune it"

41...my auto electric guy took gen and reg back to shop and tested there and everything working......he told me to polarize it on the truck when running at idle....which I did and still nothing.....this has an ampmeter

[rustydog]

The diagram is for a neg ground system , same for positive ground just different battery terminals

Disconnect the generator from the regulator (probably easiest to simply take the wires off the generator).

Connect a jumper from DF on the generator to the generator frame. Now run the engine and measure the voltage from ground to D+ on the generator.

NOTE: Some generators have different types of terminals;

verify which is DF and which is D+.

As you increase the engine speed, the voltage should jump up to +25 volts or so

If it passes this test, the generator is good.

(Don't run this test longer than necessary as it will overheat the generator.)

the generator on this is an old delco..which was rebuilt...terminals are a f g.... in my research...it is mentioned you have either an a type or b type circuit....which would this be?? Here is another clue...when putting running lights on, ammeter shows slight discharge. with key switch on..lights off..turning on heater motor shows nothing on ammeter...and when running..shows nothing charging.

[rustydog]

yes get your grounds installed!!!! this will cause all sorts of mysterious problems, eng. needs to be gnd. to frame, frame needs to be grounded to the body, if in doubt add a ground to many are just enough.

also you can test the gen. on the truck un hook the wires and drop the belt. I looked on line but cant find the directions if I remeber right you gnd the frame and power the field. and armature should spin. this will tell you if generator is functioning properly.

IF ANY ONE ELSE KNOWS THIS TEST PLEASE CHIME IN

ABSOLUTELY..gearhead...its next on my list to do ...everything except engine is grounded...thx

[theakerstwo]

Here is the way we was testing them years ago. This would be a A circuit like most all large trucks used with a 50 amp gen. Make sure you have a good ground to the gen from the reg.If non then install and it don't need to be more than a 14 ga wire. Remove belt and jump from the batt to the arm ter on the reg and the gen should motor over. Then when its motoring ground the field ter at the regulator and this should slow down and almost stop the gen.That proves the gen will charge. No way to test the reg with out a tester but make sure first that the batt wire to the reg from the batt will carry current. Back in the day I would do a load test of 50 amps on that wire and the volts should stay about 12v with a load on it.

[gearhead204]

well rusty dog sorry I wasn't much help but I knew that their was REAL HELP out there thanks guys

[41chevy]

41...my auto electric guy took gen and reg back to shop and tested there and everything working......he told me to polarize it on the truck when running at idle....which I did and still nothing.....this has an ampmeter

I haven't dealt with Generators for about 20 + years but still had all me tech stuff, wish it helped. Kind of a dumb question but are you sure the amp gauge isn't the culprit? They do occasionally good south. Can you hook in a temp one to see? Paul

[thomastractorsvc]

stop wasting time and money and taking the chance of ruining your battery's and regulator, spend $100 and put an alternator on it.

A generator system is considered unreliable because of all the things that can fail, it is old technology that not only saps your batteries but your wallet.

My dad swore by that system because of it will allow a gas engine to run without a good battery so he felt if could get the tractors started he use it and when time allowed fix it, long story short he spent a lot of evenings working on the systems and repolarizing and checking grounds and replacing batteries. When I got older talked him into putting on a used 12v GM alternator on the John Deere 3020 with in a month everything that had a generator on it was changed one over to an alternator. And just like that battery's only needed to be replaced when some one stole them or years later, everything started and ran just fine.

BTW that John Deere 3020 still works and has the same used alternator on it that was put on at least 30 years ago.

[rustydog]

stop wasting time and money and taking the chance of ruining your battery's and regulator, spend $100 and put an alternator on it.

A generator system is considered unreliable because of all the things that can fail, it is old technology that not only saps your batteries but your wallet.

My dad swore by that system because of it will allow a gas engine to run without a good battery so he felt if could get the tractors started he use it and when time allowed fix it, long story short he spent a lot of evenings working on the systems and repolarizing and checking grounds and replacing batteries. When I got older talked him into putting on a used 12v GM alternator on the John Deere 3020 with in a month everything that had a generator on it was changed one over to an alternator. And just like that battery's only needed to be replaced when some one stole them or years later, everything started and ran just fine.

BTW that John Deere 3020 still works and has the same used alternator on it that was put on at least 30 years ago.

Rob, I will probably end up going that route......while I can do alot of things, electric theory is not one of them! BUT..I am stubborn about finding out WHY AND WHAT is wrong with my setup.....gets very frustrating to not be able to find the right person locally who probably can find out and help to correct problem....this crap is holding me up from finishing and finally getting some pics up of the truck..THANKS for the advice.......

[thomastractorsvc]

That's another problem with old stuff like that, subject matter experts are hard to come by anymore because it is obsolete technology and to find problems in a system like that you can do it with out much knowledge of the system if you are well versed in automotive electrical theory.

Most techs if they cant hook a OBD/computer device to it to tell them where the problem is they cant trouble shoot it and most have a hard time to find an obvious broken wire. It takes some time and patients to trace and check electrical systems and the right tools and know how to use them. If you plan on doing a lot of it spend a couple bucks and buy the power probe http://www.powerprobe.com/pp3.php or at least a good multi-meter and test light that is powered