Alternator question

[rrlund]

If you hook a jumper wire straight from the post on a Delco single wire alternator to the positive post on the battery, should it charge if it's working?

The alternator worked before I started pressure washing and painting on the tractor, but doesn't now after I painted it. Angry Bob King and I theorized that maybe I sprayed paint in somewhere that it shouldn't have gone.

The idiot light used to come on when I turned the key on, then went off after the tractor started. After I sand blasted the dash and pressure washed in that general area, it doesn't come on anymore. I can't see in there very well, but I shined a light up there and felt up in there too. I can't see or feel any wires off.

I have no power to the post on the alternator with the key on or off. I hooked a jumper wire directly from the alternator and have 12.05 volts at the battery and the alternator both when it's running and when it's not.

 

[used red MN]

First off yes it should charge only connected with a jumper wire, IF it is a true one wire alternator. However, your statement that the idiot light used to come on and go off after the engine started does not coincide with a one wire alternator. The Delco 10si when converted to a one wire configuration has no means to provide an idiot light. The idiot light is operated by the excite circuit of the voltage regulator on a 3 wire configuration. There is a possibility that the idiot light you thought was for the charging circuit was instead an oil pressure light. WHAT TRACTOR? I would suggest to pull the alternator apart and check for free movement of the brushes and shine up the slip rings.

 

[Dieseltech]

All the one wire Delco alternators I have work soon as the engine is started, sometimes they need sped up a bit if the alternator pulley is larger which slows it down. Is there any paint on the connections? I've seen paint cause trouble, and once cleaned off trouble was gone. Saw that happen before on a friends restored Oliver 660, it was just painted, but died after running five minutes out of the shop. Test light showed no power to the key switch, cleaned the paint from the starter hot cable post and all was fine again.

 

[NDIHC]

If the light bulb in the charge indicator ( idiot light) is burned out it will not turn on with the switch and the alternator won't charge.

 

[NDIHC]

That's assuming that you don't actually have a one wire alternator. A one wire doesn't have an idiot light. Is there a 2 terminal connector plugged into the alternator? Is it possible there is supposed to be one that got knocked off during cleaning? If you have an idiot light you need that 2 terminal connector.

 

[rrlund]

Oliver 600/David Brown 990. The light thing is odd to me too. It didn't actually have an idiot light to begin with. There's a small hole drilled in the dash and I could see a light come on down there when I turned the key on. It would go off as soon as the tractor started. When I looked up in there today, all I could see was a light socket that looks like it should be plugged in to the back side of a gauge or the tach or something. There was no bulb in it. I might have blown it right out with the pressure washer.

I thought somebody way smarter than me had rigged it up as a make shift idiot light. It's a one wire Delco for sure. The tractor originally would have had a Lucas generator. Like I said, it worked before I started cleaning it up and painted it. I took the wire right off the post and checked it with the meter and a test light. I don't know why I'm not getting power to it from the battery. It should be hot, either with the key on or off, but I would think either way. If the alternator actually works, you say it should charge by just running a jumper wire to the post from the positive battery terminal, correct? None of the connections were off when I painted it, so that's not the issue.

I did put a new switch on it during the process. I got it from DB Parts LTD and they said it was the correct switch for the tractor. There are 4 posts on the switch. I thought I had it hooked up the same as the old one. There are five wires. Two go in to the same connector and go on one post that only has power when the switch is on. Another one hooks to the other post that only has power when the key is on. The other two hook to the posts that have power all the time. One or both of those has to be coming from the solenoid to provide live power directly to it. What has me confused is why none of those wires is putting power to the alternator post at all, switch on or off.

But still, just using that jumper wire to the battery, the voltage doesn't change with it running.. Yes, I revved it up. Not my first one wire alternator.

 

[moresmoke]

I would suggest running a ground jumper from the alternator case to the neg battery terminal. As others have said a one wire alternator does not have an idiot light.

The moment I read about painting, my first thought is that your alternator is no longer grounded well.

 

[rrlund]

I didn't have it off to paint it.

 

[used red MN]

The alternator should have power all the time. Obviously someone had to create that circuit when they changed it to an alternator. I do not know about the Lucas generator circuitry but in a Farmall if you know what your doing you can use the original generator wires for the alternator conversion all you need to do is make a connection between a couple original wires when you remove the voltage regulator. Inn general you do not want the extra amperage the alternator puts out running through your ignition switch circuits, same applies for the generator output for that matter. When you have an ammeter the power circuit for the alternator goes through that. From what I can find that tractor does not have one. Follow through with my suggestion to look at the alternator. Maybe you have never had an alternator apart. No voodoo in them. Mark it so you clock it the same when you put it back together. All you need is a straighten paper clip to hold the brushes in to put it back together. If you sand blasted around the alternator hold the back end up when you pull it apart so sand does not fall in the back needle bearing. There is a possibility that pressure washing disconnected a poorly devised feed circuit to the alternator.

 

[rrlund]

So if I need to run a new wire to the alternator, I could just run it from the starter solenoid where it's hot all the time and not even go up under the dash or near the switch just to simplify things since it doesn't have a gauge or idiot light? The 500s have three gauges, oil, temp and ''battery condition'', along with a tach. I'm not going outside right now, but I'm 95% sure the 600 only has oil and temp gauges., as well as tach.

 

[used red MN]

Yes, it could be wired directly to the starter solenoid. A ..battery condition.. indicator is interesting. I was going to say earlier that it would take some fancy circuitry back in 1960 to create a dash light that monitored battery voltage and turned a light off or on based on several parameters. They probably had the technology, it just was not used on a tractor. Get up into the late 60s and solid state regulators this would have been more likely at that point.

 

[rrlund]

It must be the wire monkeyed up somewhere. I put the charger on it all afternoon while I was cutting hay. I unhooked it when I got home, checked the voltage with a meter and had 12.45. I put a jumper wire to it from the solenoid to the post on the alternator and started it. I checked it again with the meter and had 13.something. I'll have to track it down when I get done with the hay.

 

[Traditional Farmer]

How old is the alternator? Some of the older ones that were 3 wire converted to one wire had issues,the modern ones I've gotten from DB Electrical have been trouble free.

 

[rrlund]

No idea. I bought the tractor a year ago. I don't think the alternator would be the cause of the wire going to it not having any juice to it whether the tractor is running or not.

 

[Traditional Farmer]

Right there the wire on a one wire alternator need to be hooked directly to the hot side of the battery,I hook at the solenoid where the battery cable hooks with at least 12 ga wire.No fuse either as with a 62 Amp Alternator fuses will blow quick.

 

[MARK ROBKE]

Maybe that light is oil pressure? Mark.

 

[RodinNS]

If it has a 1 wire as you say then there would be no idiot light. What you have on the dash could be an oil pressure or intake restriction light or any number of other things someone added.
So back to the alt... I'd say something got wet or corroded from sitting. Possibly the slip rings are corroded and you could disassemble and clean that up. Otherwise I'd say it has a bad regulator, assuming of course that it will not charge even at full throttle.

Rod