Generator Woes

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Generator Woes

Postby ScottyG » Sat Dec 04, 2004 1:37 pm

Well, I received and installed my rebuilt generator. I even had the guy test my VR and both were operating very smoothly on the bench. After putting everything back together, I put 3in1 oil in the cups and fired Henry up. Positive reading on the ammeter!!. I let the tractor sit at just above idle for about an hour to charge the battery. Suddenly, I noticed the ammeter die. I shut the tractor off and tried to restart. No dice, I had to crank by hand. Turned the lights on and they work fine. Try to crank the engine again and it barely turns.

I ran a continuity check for ground from the generator. It is grounded fine. When the lights are on, the ammeter reads - so that is working fine. I checked the voltage across the battery and the needle never moves. Doesn't appear to be charging at all.

Now I'm starting to think that something is wrong with the generator again. Maybe I put too much oil in the cups and some got on the brushes? I'm reaching here but I'm absolutely confused as to what could have gone wrong. Has this ever happened to anyone else? BTW, the generator received a new armature.
"Henry" 1948 Farmall Cub

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Postby Cub-Bud » Sat Dec 04, 2004 1:57 pm

Most generators today are rebuilt with sealed bearings, eliminating the need to oil them. That might be the problem.
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Postby ScottyG » Sat Dec 04, 2004 2:05 pm


Great. Thanks for your help. Looks like I'll have to reverse everything I've done to get him running.
"Henry" 1948 Farmall Cub

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Postby beaconlight » Sat Dec 04, 2004 2:48 pm

Really need to know which one of the various wiring configurations you us. Is there water in the battery? Did you polarize the gen when you installed it?
Do you have a good ground to the battery and at the battery? I clean and grease battery connections to keep them from oxidizing. Make sure that they are clean and tight. Do you have good connections at the bat connection at the starter? Does the battery take a charge from a charger? If it does you can use the charger as a test device.
First hook up to the battery terminals. Does it take a charge? No = bad battery. Yes = move the hot lead(the one that does not go to ground) to the battery post of the starter. Does it charge? No= bad connection in the wiring or connections to the battery. Yes = connect the hot lead to one side on the Amp meter. Try both sides of the amp meter if you are not sure which one goes to the starter. If it charges from both sides the amp meter and the wiring are ok. If only from one side then you have to figure out whether it is the wiring or the meter. If it is good from both sides move the hot lead to the batt term of the regulator. Does it charge No= bad wiring yes = let us know which wiring diagram is yours and we can go from there.
You can ground the F term of the generator and if it is good the voltage will go up and the lights will brighten considerably. You can also see it on your volt meter.
Many people are frightened with electrical problems. There is no need to be. Electricity is the most consistant thing you will ever meet. Closed circuit = electricity flows. open circuit = no electricity flow. Break a problem in to a set of yes and no questions and most troubles find them self or you prove what is not bad. Use what ever test tool you have available. A battery charger doesn't come with a tag that says "TEST TOOL" but as you can see it can be used as one. I made no reference to 6 volt or 12 volt and non to + ground or Neg ground. This way will work with any combination of volts and ground.
The most important thing I found in 34 years of shooting Telephone troubles was KISS Keep it simple stupid. When I did that only the first three leters were operating. When i didn't keep it simple only the last word covered the topic.

Again if it is good to the Batt term let us know which wiring diagram is yours.

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Postby ScottyG » Sat Dec 04, 2004 4:09 pm

Thanks for of the advice, Beanconlight. My wiring is battery ignition. The confusing thing is that my generator was working and suddenly it isn't. I can't rule out a bad battery. It's the original that came with the tractor when I bought it last May. However, even if the battery is bad, wouldn't I see something on the ammeter? I tried testing the voltage from the F term to ground and it barely registered. This tells me that it's not the regulator I should be worrying about. I think I'll need to take the hood off again, open the generator inspection band and see what I see. I hate to do this since the generator was rebuilt but what are you going to do? I suppose it could be a stuck relay on the VR but by grounding the F term, this should bypass the regulator. I doubt very much it is the ammeter or the wiring to and from it since I show a (-) charge on the ammeter when the lights are on.

The other thing I would ask is grounding. If I disconnect the battery from the circuit, the engine dies, which, I believe it's supposed to do. If the battery leads weren't making good contact or it had a bad ground, I would assume that the tractor wouldn't run at all right?

Well, I'll run through the troubleshooting diagram and see what happens. Pretty frustrating.

"Henry" 1948 Farmall Cub

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