Charging amps and Headlights?

[Jim]

When riding my VL, I get 4 amps showing on the AMP gauge at about 35-40 mph. This is OK and what the Riders Manual says the amp rate should be charging at. HOWEVER, when I turn on the headlight, the amps drop down to 0 to -1 amps output. Of course a higher speed and engine revs will bring up the amps, but for around town 35-45 mph. is the limit. This happens with both of my VL's. One is an electronic regulator and the other has the original type. What is wrong? If I move the 3rd brush, then it could overcharge without the headlight on, and I don't want to ride with lights all the time. Both generators for both VL's will charge while riding with no lights, but as soon as I turn on the lights... 0 amps. Would this have anything to do with the fact that I have a tiny 6N6-3B 6V battery? Would a BIGGER battery be any different?

Forgot to ask... is there a way to "test" a voltage regulator?

[tfburke3]

When riding my VL, I get 4 amps showing on the AMP gauge at about 35-40 mph. This is OK and what the Riders Manual says the amp rate should be charging at. HOWEVER, when I turn on the headlight, the amps drop down to 0 to -1 amps output. Of course a higher speed and engine revs will bring up the amps, but for around town 35-45 mph. is the limit. This happens with both of my VL's. One is an electronic regulator and the other has the original type. What is wrong? If I move the 3rd brush, then it could overcharge without the headlight on, and I don't want to ride with lights all the time. Both generators for both VL's will charge while riding with no lights, but as soon as I turn on the lights... 0 amps. Would this have anything to do with the fact that I have a tiny 6N6-3B 6V battery? Would a BIGGER battery be any different?

Forgot to ask... is there a way to "test" a voltage regulator?

The amp gauge doesn't show generator output but the difference between gen.output and load or whats coming and going to the battey..So if when you turn on the lights and the amp gauge shows 4 0r 5 amps less going to the battery,thats the load of the lights.
Tom

[Jim]

I never thought of it like that... but what could be my problem then? Generator? Or Regulator? Anyway to do a "home" test rather then sending it out?

[RvP]

I have experienced this before with a VL a Chapter member had. Charged great until the lights went on and had similar readings on the ammeter. I only have experience with the 32E generator and I assumed the generator on his VL was similar. The VL wiring was stock and seemed to be wired the same as my 32E on my WL, i.e. when the lights go on a second field in the generator is excited to boost the generator’s output.

Using a handheld compass I went over to my WL (with the engine not running) and turned the lights on. This energized the second field in the generator and I noted the polarity of the compass. Did the same on his VL’s generator and the compass showed the opposite polarity. As a check we did the same on a knucklehead with a 32E and the compass polarity agreed with my 32E.

We pulled the generator out of the VL, opened it up and swapped the secondary field connections and the problem was resolved. Evidently when the generator was rebuilt the lighting field was not wired correctly. The lighting field was opposing the regulating field (i.e. 3rd brush field) which significantly reduced the output of the generator.

Another time I worked on a panhead with a 32E that was not charging sufficiently when the lights were on. First check was that the lighting terminal on the generator had 6V on it when the lights were turned on (engine not running). There was no voltage on the terminal and traced it to a wiring issues. Corrected the wiring, got 6V on the terminal and problem solved.

The above are two areas I found with the 3 brush generators that I have encountered. You can run the following tests with the engine not running to verify the lighting filed is working and connected properly:

1) Turn the lights on verify there is 6V to the lighting terminal.
2) Turn off the lights and removed the wire on the lights in coil and do a continuity check to make sure the field isn’t open.
3) Put the wire back on and turn on the lights. Using a handheld compass move it around until you find the “sweet spot” where the compass needle points directly to the generator. Do the same on a similar 3 brush generator and the compass polarity (i.e. north/south) should agree. If not the lighting field wires need to be reversed.

Testing a voltage regulator off the motorcycle requires equipment that most people don’t have. It is best to verify the regulator is working on the motorcycle using a voltmeter and the instructions provided by the manufacturer for trouble shooting.

Ronald V. Papasso

[Jim]

Thanks Ron for that help. YES, I have the 32E generator on this bike. The only thing I know for sure is that the headlight does come on when I turn the switch.

Tomorrow I will see what I can figure out (if anything) as per your instructions. I am not sure if I have any compasses anymore.... I'll have to ask around. Then again, I don't have a 32E gen to compare it too.

Ya know, funny thing is... I am also in the Seaboard Chapter... Check your PM.

[Jim]

Just to update this thread.... Today (Sat. 10/5) I worked on the Generator and found that it wasn't as easy as switching the two wires around on the Shunt Field. When I looked closer after I removed the Gen I saw right away that there was NO WIRE attached to the "Switch" terminal, and also no wire attached on the Neg. (-) brush. I could then plainly see that the Shunt Field had NO wires coming out of it at all. Probably years ago, it either shorted out, or "who knows" but someone had cut them all the way back. At that point, I knew I had to take the Gen all the way apart to replace the field. So, I have no idea of where the wires are, but someone had removed them all the way. They took the time to remove the ends from the (-) Neg. brush and terminal too.

Would it be "best" to replace regulating field as well? I KNOW that one works and it has good continuity through it. hmmm...

[Jim]

I thought I would add a photo of my Gen. field. The Shunt field (without wires) is on the right. The Shoes are just sitting in there, and not stuck or anything like that. I am not the one that cut the wires, and I am going to assume that the field had shorted out and the previous owner had cut the wires.