Cannuck Posted September 24, 2017 Report Share Posted September 24, 2017 Hi again I am the owner of a 1948 Canadian built dodge sedan. I have a problem with the charging system. I don't know if its a generator problem or a voltage regulator problem. Last evening was the first time this year that i had to use the headlights. They were quite dim by the time I had travelled the 10 miles to home and today i have been charging my battery. The problem starts in the spring when i had installed the battery wrong. I had made it a negative ground .I drove it like that for a couple of months before being convinced the it should be a positive ground. I was told I would have to re polarize the system . We used a jumper cable at the voltage regulator to accomplish this but the gentleman helping me thought there was a problem because there was very little spark . I had to take his word for this because i am no mechanic , Is there an easy way to check the generator ? Where do i start? I could remove the generator but i am not setup to do a bench test .I would appreciate any suggestions. Thanks John Quote Link to comment Share on other sites More sharing options...
DonaldSmith Posted September 24, 2017 Report Share Posted September 24, 2017 Has your ammeter been working? Headlignts on, needle goes negative. Assuming the motor is running above idle, the generating system should start to move the needle back to neutral. If the battery is not fully charged, and the headlights are off, the needle should show positive, until the battery is more fully charged. Quote Link to comment Share on other sites More sharing options...
Cannuck Posted September 24, 2017 Author Report Share Posted September 24, 2017 Yes we tested that yesterday i put the headlights on with the motor not running and the ammeter showed negative one bar of centre. Then i started the car and it stayed the same . when I am driving the car with the headlights off the needle stays on centre. Quote Link to comment Share on other sites More sharing options...
DonaldSmith Posted September 24, 2017 Report Share Posted September 24, 2017 I looked in the "electrical" section of the shop manual for my DeSoto, but didn't find a step-by-step procedure for "generator not charging". Instead it talks of a generator bench test, and various tests for the regulator. Some experts will have to chime in here. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted September 24, 2017 Report Share Posted September 24, 2017 Quote Link to comment Share on other sites More sharing options...
Cannuck Posted September 24, 2017 Author Report Share Posted September 24, 2017 Hi Don My voltage regulator is simular to the ford regulator. Yesterday i thought he jumped from B to A. Quote Link to comment Share on other sites More sharing options...
Cannuck Posted September 25, 2017 Author Report Share Posted September 25, 2017 Hi Don I touched field to batt. got a little spark . With everything back together turned on the headlights with the engine running ammeter wet negative and stayed there even as I revved the engine . Quote Link to comment Share on other sites More sharing options...
greg g Posted September 25, 2017 Report Share Posted September 25, 2017 To check the generator field coils, make a jumper wire with alligator clips on each end, if you make it 4 to 6 feet long you can use it for other testing also. Clip one end to the field terminal of the gen. I believe it is the thinner of the two. Start the car and adjust the idle to about 800 to 1000 rpm. Then attach the jumper wire to ground. The amp gaugeshould peg at full charge as this ground bypasses the regulator. If it pegs this indicates the fault is in the regulator. If it doesn't it suggests a fault in the generator. The first place to look in the Genny is the continuity to and through the field windings. Only leave the ground connected long enough to check the gauge. If left on and charging, it will start melting and spitting solder from the armature. Quote Link to comment Share on other sites More sharing options...
SpitfireM37 Posted September 26, 2017 Report Share Posted September 26, 2017 7 hours ago, Cannuck said: Hi Don I touched field to batt. got a little spark . With everything back together turned on the headlights with the engine running ammeter wet negative and stayed there even as I revved the engine. Your going to get a little spark. I do at least. That illustration of where to polarize is great. I have been having the same issues with mine. I rebuilt the generator, cost 40 bucks, and still had some issues. I cleaned all my grounds and that seemed to be the last part. Previous said, there is a reason vehicles don't use generators anymore so I'm swapping to an alternator. Good luck! Quote Link to comment Share on other sites More sharing options...
Cannuck Posted September 27, 2017 Author Report Share Posted September 27, 2017 Hi Greg g . I did the test ,and according to m manual the field terminal on m generator was the thicker of the two. I had no change to the ammeter after attaching the other end of the cable to the bracket that holds the generator and increasing the RPM.I assumed that this was ok as a ground. Quote Link to comment Share on other sites More sharing options...
greg g Posted September 27, 2017 Report Share Posted September 27, 2017 My manual drawing shows the large terminal on the gen as the armature terminal, which makes sense as it would be carrying more current than what is needed to energize the field. So your problem might be the reg is wired wrong. Thin to field, thick to armature test again. Center reg terminal is field. Verify and test again. Quote Link to comment Share on other sites More sharing options...
Cannuck Posted September 27, 2017 Author Report Share Posted September 27, 2017 Hi Greg Thank you for your help I did as you suggested and still no peg to full charge . i guess my next step is a trip to a shop to have the generator looked at Thanks to everyone how tried to help Quote Link to comment Share on other sites More sharing options...
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