Hello all, newbie here. I need some electrical/generator help. I have a rebuilt generator from Langs and a 6 volt voltage regulator from Langs as well. I have rewired the entire car and need to make sure everything is wired right. I have referenced the wiring diagrams and some are different and a little confusing. So I am posting pictures so you can see mine to make sure it is correct. Everything runs as it should. My question is I don't think my new generator is charging. I can depress the horn button and the ammeter will move to discharge (about 10amps). Then return to zero. It stays at zero and never moves over to the charge side. Is my wiring to the ammeter correct? I need some help! Thanks in advance.
No clue =) But those new wires sure are perty. I bet Mr. John F. Regan (maker of said voltage regulator) will see your thread and comment some time today. Others may have helpful info before then, but I doubt any can speak on the subject with the same authority.
I think worthy of noting I have not "adjusted" the third brush. I have simply installed the generator/voltage regulator. So if the ammeter is reading zero, perhaps I need to move the third brush and see if I get a different result? Is it possible to turn the third brush where it won't charge at all? In my MTFCA it appears I have the wiring correct.
Call Lang's before adjusting anything. If that generator came from the source I believe it did, that generator if A-OK.
Probably 3rd. brush adjustment as stated. Make sure batt. voltage is going to the gen. through that yellow/black wire at the cut-off. (Key on batt side, eng off & check with a test lamp. Ammeter hooked up OK if showing a discharge when using some thing electrical like horn or lights. Not charging is another problem.
Here is Ron Patterson's wiring diagram which is the one to use. Discard all others. I used it to wire my '26 coupe and it is all correct. Jim Patrick
The real test to see if your generator is working is to check the battery voltage and not necessarily the amp gauge. Check the battery voltage before starting the car and about 6.25 to 6.3V is fully charged. Then check the voltage when the car is running. If the voltage is more when running then when not, you know the generator and voltage regulator are working.
If the generator is working then the question becomes, how much is or can it generate when needed? Still a voltage reading can check that. With full load (lights on), is the battery voltage still higher then 6.3 volts? If not then the third brush may need adjusted.
That's what I'd do anyway.
If you have access to a known good cutout or diode cutout, even if you have to borrow it from someone else in the club, put that on the generator and see if the ammeter shows charge when you run the engine. If your ammeter still shows zero amps, your generator is not charging. You should also be able to read 6 volts on the battery side of the cutout when the engine is not running but zero volts on the generator side when the engine is not running. Then with the engine running the voltage should be a little higher and same on both sides of the cutout. you
If the above tests are OK, then install your regulator. If the ammeter shows zero, you have a problem with the regulator.
FIXED!! Ok, so it was the third brush adjustment. I loosened the nut slid it just a little and whamey! 10 amps of charge. Since I don't do any night driving I am going to leave it at the 10amps...I am happy, happy, happy!!
Whoopsie...I was wrong. Lesson learned!
Not so fast Rob,
For for the best generator health and the way you drive maybe 3 to 4 amps would be a good charge rate. Read John Regan's post at:
Review the Fun Projects regulator instructions.
I believe the battery should have some time on the charger prior to setting the third brush, and the third brush adjustment procedure with the regulator should be reviewed
Good info. Also was thinking if generator was polarized prior to regulator installation.
Good point, I may tone her down a bit to 3 or 4 amps. It's amazing something as simple as seeing an ammeter needle move in the right direction can be exciting.
Read the voltage regulator instructions over and over about 10 times and then set up the genny accordingly otherwise you risk killing it which will be expensive.
Good point, if in doubt, read the instruction. They can be found at:
Essentially under the "Setting the generator third brush" section.
Just a few comments. The 3 or 4 amps being mentioned is the correct rate when the charge rate is constant using a cutout. You are using a VR so follow the instructions that came with your VR and follow them to the letter including the final test which occurs a few days later. Conventional wiring uses the left most firewall connector for the yellow/black wires, the next one (#2) for the red wires that go to the magneto, the next one #3 goes to the hot battery leads and is for the solid yellow wires. I noted you have done it different - any particular reason? Is the third wire hiding under the yellow/black connections the horn hot wire? The switch wiring you pictured looks OK with regard to the wires I was mainly interested in which are the solid yellow and the Yellow/black wires. Those are the main charging path wires.
Your horn should NOT draw 10 amps unless it is a 6V horn and you are using it on 12V which is not what you stated. Factory battery horns were adjusted for 5 amps max and loudest sound at that 5 amp setting. Check that out since you could end up with a burned out horn rather quickly. You can leave the setting at 10 amps if in fact that is where it is but if you just moved it a bit and saw that much charging then your 3rd brush might be no where near 10 amp setting but the VR is allowing that much charge so your charge rate is at LEAST 10 amps but might be more. I strongly suggest you take the time to properly setup the VR per the instructions that came with it.
For sure the terminal block is wired incorrectly. It will work but could be a problem if someone else works on the car and is using the wiring diagram. The wire colors don't stay bright forever.