Gen. Light coming on

Electrical issues
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Hauula Pan
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Gen. Light coming on

#1

Post by Hauula Pan » Sat Apr 10, 2010 7:50 am

I have a question about my Generator light. When I 1st start up the light usually goes right out but sometimes it doesn't. If I click over & turn the lights on it will go out. Also sometimes when starting with just the ign. on it will go out but come back on at idle and go out as RPM is increased. I'm thinking this is all normal with a 6 volt relay system. Now here is the strange part, as the bike warms up the light comes on at idle and takes increasing RPM to put it out. Where it would go right out just a bit above idle cold, it takes more & more RPM to put it out as it gets hotter. I'm guessing this is not normal? I really can't tell if I'm getting a charge back to the battery with just a volt meter and don't have an amp meter. I'm wondering if there might be an issue with the relay or if the 3rd brush needs adjusting? I don't know of any way to properly set the 3rd brush without an amp meter. Can it be done accurately with a volt meter? And do I even have a problem? This is the 1st time I've ever had the light hooked up. In years past I never had a working light & my only indication that there was a charging problem was when the battery would run down & the bike would die. So far it seems to be charging but I've not taken it on any long rides yet. Could use some ideas.



cole
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Re: Gen. Light coming on

#2

Post by cole » Sat Apr 10, 2010 9:56 am

Almost sounds like the oil pressure light, just saying cause that's what mine does. cole

Frankenstein
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Re: Gen. Light coming on

#3

Post by Frankenstein » Sat Apr 10, 2010 1:26 pm

The generator is working, but the output is somewhat low.
When cold, the battery has set for awhile and its voltage is slightly lower. Start the motor, and the generator's output is high enough to put out the light at lower RPMs. As time goes by and the battery takes on charge, its voltage goes higher. Now the generator has to turn at a higher RPM to match the battery's voltage, and turn out the light.
When you turn on the headlight, you add an additional field into operation, which is fed directly from the battery. This immediately creates a strong magnetic field inside the generator and ups the generator's output, and the light goes out.
Without meters, you could slightly rotate the 3rd brush clockwise and probably resolve the issue. However, it would be a good idea to check and see if the commutator/brushes have gotten dirty, perhaps from oil getting past a worn armature shaft seal. The commutator doesn't have to be shiny copper, a smooth blackened surface, with all commutator segments clearly insulated from each other, is o.k. But heavy deposits and "stuff" bridging the segments are going to affect operation.
Good luck.
Dick

Hauula Pan
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Re: Gen. Light coming on

#4

Post by Hauula Pan » Sat Apr 10, 2010 6:18 pm

Dick, that sounds right on. My only concern with adjusting the 3rd brush without an amp meter is I don't want to go too far & over-charge. I don't think you can get any kind of accurate reading using a volt meter because battery voltage is always changing with the load & condition of the battery. I mean you can get a general idea that your generator is working if the voltage increases with the engine running but you can't tell how much its actually putting out amp wise. I'm thinking if I let it warm up to running temp. & just shift the brush enough to put the light out at cruising RPM it might be ok, but I sure don't want to start cooking the battery. Been there & done that in the past & it really makes a nasty ugly mess of things. But I also don't want to under charge either because as we all know a Pan running 6 volts dies on the spot as soon as the battery gets even a little low. Guess I really need to find someone with an amp meter or roll the dice & risk the over charge. Thanks for the feed back. And yeah you 12 volt guys I know I wouldn't have this problem with a regulated 12 volt system, but 6 volts is what it came with and me and the bike are both pushing 60 and we're both old & stubborn.

hogboy52
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Re: Gen. Light coming on

#5

Post by hogboy52 » Sat Apr 10, 2010 7:16 pm

The amp meter tells you nothing but the load, which changes all the time. Adjust it with a volt-meter to 6.8 volts at the GEN terminal, lights off, motor revved up.
If you run the lights at all times you might want to adjust it with the lights on. the boost field is a "positive feedback" system and can become unstable if in continual use.

Hauula Pan
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Re: Gen. Light coming on

#6

Post by Hauula Pan » Sat Apr 10, 2010 7:30 pm

Thanks, I didn't think about using the volt meter at the gen. instead of at the battery. DUH.... OK back to work now.

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Re: Gen. Light coming on

#7

Post by Frankenstein » Sat Apr 10, 2010 8:23 pm

If you don't have the ammeter, the voltmeter will do the job. It really doesn't matter, battery or gen terminal, as they are both connected by a piece of wire, right? They should be equal minus the drop of voltage in the wire due to its resistance.
Installing 65A fields, taking out the 3rd brush, and adding your favorite 12v regulator will make your 3 brush genny a 12 volt genny. Not the optimum solution, but inexpensive, servicable, and reliable. Running a 100W Halogen light sure helps to see wildlife at night.
Dick

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