New alternator

[Beckwith tree farm]

I have a ford naa tractor. I converted it from 6 to 12 volt about 5 years ago.
The alternator died. so I ordered the same one AC delco one wire alternator. I can't get it to produce any electricity. Anybody have any ideas?

 

[Texasmark]

I haven't touched one for decades but I recall that 12v has to be applied to the unit (to power the electronics internally), and then the engine RPMs have to be above a certain speed for it to start generating. On mine, if you idled down the tractor, say around 600 RPM mine wouldn't produce any output.....again, been a long time and my memory may be in question.

 

[Beckwith tree farm]

I revved the engine up as high as it would go.nothing!

 

[DanielW]

Which Delco did you order? How many amps? A problem with a lot of Delco 1-wire's (or knock-off equivalents) on these old tractors is that they often require a minimum RPM for excitation - often more than they typically achieve on an old, slow-revving tractor. And the higher the alternator amperage, usually the higher the excitation RPM. Back when the standard 1-wire's were only 35-40 amps, they'd excite at very low RPM's and they'd be dandy for any old tractor. These days it seems most 1-wire's are 63 or more amps, and usually require higher excitation RPM's. The 63A models are usually (but not always) ok on older tractors. Higher amperages are more problematic. And the RPM is, of course, also dependent on what size pulley you have on it. What diameter does the new alternator have on it? Have you tried revving it up high to see if it's charging? Once they're excited, they'll still charge down to any low RPM.

Another common problem is grounds: The 1-wire's need to be grounded through the mounting bracket, so if your bracket isn't making good contact with the block (or alternator not making good contact with the bracket), it won't charge. Most Delco's have a spot for an auxiliary ground wire you can wire between the alternator housing and somewhere on the block. It's quick and easy to run a temporary jumper from the alternator to the block to see if that's the issue.

Let us know what amperage the new alternator is, and what diameter pulley is on it. And if you' haven't yet, try making a good ground between alternator and block/frame.

The good news: Most 1-wire's can also be wired as a 3-wire, so if you need to it's quick & easy to wire it as a 3-wire to have external excitation, so you don't have to worry about the excitation RPM. One thing to keep in mind if you wire it as a 3-wire: You'll need to wire the excitation wire through an LED, indicator, or diode to not backfeed and keep powering the coil when you shut down: It's pretty common for an incorrectly-wired 3-wire to let the tractor keep running when you turn the ignition off. The quickest/easiest way is to buy one of the pre-made spade connectors for these 3-wire alternators because they already have a diode wired inline with the excitation terminal. But half the ones you buy these days have the diode in backwards, so you need to cut it out and flip it around. Very easy to run temporary wires to the alternator to temporarily have it like a 3-wire to know if that's your issue.

 

[Beckwith tree farm]

Thank you for the reply. The pulley was bigger on the new one I switched them. The engine is grimey so I ran a extra ground wire. It must be a ram issue like you said only thing I can think of!

 

[Beckwith tree farm]

Rpm

 

[DanielW]

If it were me, I'd get some temporary wires with spade connectors on one end, and wire it like a 3-wireto see how it does. Not all 1-wire's can be wired like a 3-wire, but 90% of them can be. Can you share what specific model of alternator you bought?

 

[MeanGene1]

The ones that are sold on this site are set up to excite at low RPM and work very well. The kit comes with the right size pulley and belt for tractor use, and will excite just off idle. I have used them on my 8N and my 850 and very pleased with them

 

[ratface]

I have one on My 8N, sometimes it takes a drive around the barnyard before it gets going, that said sometimes it has to be jumped between two of the connectors to get it going again, especially if it sits for some time. There are post on here about which two connectors to jump, (Dell, an oldtime member had made many posts about the jumping procedure) You can just bend a pc a wire into a U shape to jump it. I remember I had to dig out some silicon that came applied over one of the terminals to jump. I just keep a pc of tape over it now to give me acess whenever it needs jumping. On mine I have to get into the high rpms to show it charging and if the battery has a full charge the ammeter will start to creep back down to zero again.

 

[Charlie M]

I have been buying a mini alternator from my local starter/generator repair guy and they work great. They are single wire, charge at much lower RPM and don't take up anywhere near as much space as the larger ones. If all you are running are occasional lights, ignition system and charging the battery they are the way to go.

 

[DanielW]

I have been buying a mini alternator from my local starter/generator repair guy and they work great. They are single wire, charge at much lower RPM and don't take up anywhere near as much space as the larger ones. If all you are running are occasional lights, ignition system and charging the battery they are the way to go.

That's good to know. I've been eyeing those mini alternators for a few years wondering how well they work and what the excitation RPM is for them. There are certainly several cases where the smaller size would be more convenient to fit in the same footprint as the old generators when doing a conversion. For 99% of the old tractors folks on here talk about, even 20 amps would me more than adequate.

 

[Beckwith tree farm]

Were would i get a mini alternator?

 

[Beckwith tree farm]

Which Delco did you order? How many amps? A problem with a lot of Delco 1-wire's (or knock-off equivalents) on these old tractors is that they often require a minimum RPM for excitation - often more than they typically achieve on an old, slow-revving tractor. And the higher the alternator amperage, usually the higher the excitation RPM. Back when the standard 1-wire's were only 35-40 amps, they'd excite at very low RPM's and they'd be dandy for any old tractor. These days it seems most 1-wire's are 63 or more amps, and usually require higher excitation RPM's. The 63A models are usually (but not always) ok on older tractors. Higher amperages are more problematic. And the RPM is, of course, also dependent on what size pulley you have on it. What diameter does the new alternator have on it? Have you tried revving it up high to see if it's charging? Once they're excited, they'll still charge down to any low RPM.

Another common problem is grounds: The 1-wire's need to be grounded through the mounting bracket, so if your bracket isn't making good contact with the block (or alternator not making good contact with the bracket), it won't charge. Most Delco's have a spot for an auxiliary ground wire you can wire between the alternator housing and somewhere on the block. It's quick and easy to run a temporary jumper from the alternator to the block to see if that's the issue.

Let us know what amperage the new alternator is, and what diameter pulley is on it. And if you' haven't yet, try making a good ground between alternator and block/frame.

The good news: Most 1-wire's can also be wired as a 3-wire, so if you need to it's quick & easy to wire it as a 3-wire to have external excitation, so you don't have to worry about the excitation RPM. One thing to keep in mind if you wire it as a 3-wire: You'll need to wire the excitation wire through an LED, indicator, or diode to not backfeed and keep powering the coil when you shut down: It's pretty common for an incorrectly-wired 3-wire to let the tractor keep running when you turn the ignition off. The quickest/easiest way is to buy one of the pre-made spade connectors for these 3-wire alternators because they already have a diode wired inline with the excitation terminal. But half the ones you buy these days have the diode in backwards, so you need to cut it out and flip it around. Very easy to run temporary wires to the alternator to temporarily have it like a 3-wire to know if that's your issue.

The replacement alternator i bought is 19135672 gm it is
63 amps i think lack of rpm's
Is the problem

 

[MARK ROBKE]

Umm.. maybe I missed it, but does your 1 wire 'hot' wire have any voltage on it when the engine is not running? Mark.

 

[Beckwith tree farm]

No

 

[Jim.ME]

Where does the other end of that one wire on the alternator connect to on your tractor?

 

[47fivewindow]

I wonder if the amp meter is open or no longer conducting. 63 amps would be enough to burn it into an open state. I would advise running the alt direct to the plus battery terminal and installing a volt meter.

 

[Beckwith tree farm]

Where does the other end of that one wire on the alternator connect to on your tractor?

To one of the post on the starter selinoid. It's all exactly the way it was with the old alternator

 

[Beckwith tree farm]

I wonder if the amp meter is open or no longer conducting. 63 amps would be enough to burn it into an open state. I would advise running the alt direct to the plus battery terminal and installing a volt meter.

Testing with a volt meter directly at the alternator should not make any difference what is going on downstream

 

[Jim.ME]

To one of the post on the starter selinoid. It's all exactly the way it was with the old alternator

At the solenoid it should be on the same post as the cable from the battery and there should be battery power and voltage on that wire where it connects to the alternator all the time. If it is connected that way, and you do not have power at the alternator, the wire may be bad.