JD 24volt charging

[CraigM]

The numbers on the alternator: 1103120***3A. Next line: 0L18 12vneg.

The*** represents 2 or 3 characters that are obliterated.

My tractor is A 5020 S/N under 25000. You send pix of other tractors and I understand for reference, but I just wanted to make sure we were on the same page.

According to the parts lists on the dealer screen, there was a short run of 5020s that used delco-remy alt, and the rest used motorolas. Mine is not in the series that specified delco, but that's what's there. As for the 12v notation on the case, it's anyone's guess. As I have said, anything is possible as hacked up as the electrical system was. I need to get the thing to make some electricity to see what it really is.

In the picture you will see 2 terminals on the left side, one above the other. They are BOTH isolated from the case, the top one is labeled BAT, the other is not labeled. I assume that the BAT one goes to + and the other to - on the 24v battery (2 12v bats in series)

The faston type terminals sticking out the top are labeled 1/R and 2/F. By this I mean that left one has 1 and R near it, and the right one has 2 and F near it.

Near as I have been able to find out, I have to put voltage on these to 'excite' things and make it work. Do you know which terminal is + or -?

I see the breaker in the picture, but don't understand how it is connected. Is this the breaker that goes between the battery interconnection/ground cable and the frame? I have heard that there is one, but can't find a good diagram of it. Even the diagrams that the dealer has don't seem to agree with other diagrams I have found.

 

[Tx Jim]

As I've previously stated the only 12 volt alt listed in 5020 parts description for your tractors SN range is for a 24 volt to 12 volt conversion not 12 volt alt on 24 volt system. Here's the parts descriptions from 5020 PC < sn -24,999. I will ask local starter/alt rebuilder if he can shed any info on your alternator ALTHOUGH I think if you attach it to a 24 volt system you are going to see SMOKE I can't determine where your JD dealer is getting his information about a short run of 5020's with a 12 volt alt but parts description in 5020 PC doesn't back up his story. All the parts photo's I see in the 5020 PC is for a Motorola Alt.

(A) 24-VOLT TO 12-VOLT START/CHARGE CONVERSION KIT

 

[Tx Jim]

Here's what I found Googling

 

[CraigM]

Tex:

They are not saying short run of 12v alts, they are saying short run of delco alts.

If you look on the online JD parts catalog, under 5020, -24999, alternator wiring, or something like that, they show that S/N 005574-007999 use delco remy 24v alt, but then they substitute a TY1447 for it and that takes you back to a generator. I didn't notice that at first. The other S/Ns below 24999 use motorola 24v alternators. It's all very confusing.

Meanwhile, I found the same tech support phone for delco-remy listed on the bottom of the catalog page you posted and called it. The guy there denied any knowledge of my alternator. He told me that the number was for a 12V unit and that they never made a 24V one with both terminals isolated from the case. He suggested that my alternator might be modified. Looking at it, it sure looks factory, but he suggested that maybe there was a kit somewhere to modify it. He also suggested that the mod might take the form of case grounding the center of the stator winding internally and causing the two isolated output terminals to be +/- 12 relative to the case. I can see that if the + half of the AC wave were sent to the bat terminal and the - half to the other terminal that he thinks was added, then the output would be 24v across the 2 outputs and the regulator would still think it was operating at 12v relative to the case. We have just tricked a 12v alternator into making 24v. It's possible. I've done similar with amplifier circuits and can't see any reason that it wouldn't work with an alternator. If that makes any sense, it might be something to ask your alternator guy.

I'm going to ask the guys at my local JD store tomorrow.

 

[Tx Jim]

Tex:

They are not saying short run of 12v alts, they are saying short run of delco alts.

If you look on the online JD parts catalog, under 5020, -24999, alternator wiring, or something like that, they show that S/N 005574-007999 use delco remy 24v alt, but then they substitute a TY1447 for it and that takes you back to a generator. I didn't notice that at first. The other S/Ns below 24999 use motorola 24v alternators. It's all very confusing.

The short runs of Delco alternators was for conversion kit from 24 volts to 12 volts. This can be established by reading footnote at the bottom of said page. I had previously viewed the parts catalog page you referred to as that's where the photo originated from that I previously posted and will post again since evidently you missed seeing it. I'm very well versed in deciphering JD parts catalogs & their parts descriptions/foot notes as I worked in JD parts departments from the mid 1960's to the late 1980's. I hope you get your alternator dilemma figured out. When you attach the wires from the 24 volt system to your 12 volt alternator would you please make a video while accomplishing the task and post it on this forum?
Thanks,Jim

 

[Dave M7040]

Likely you have a replacement Delco 12 volt. It is the most common alternator for those converting from a generator to an alternator.
There are simple and complicated ways to wire them up.
Look at this link to see the different ways to connect them.
Delco SI Alternator 1-Wire vs 3-Wire Explained
Dave M7040

 

[Tx Jim]

Likely you have a replacement Delco 12 volt. It is the most common alternator for those converting from a generator to an alternator.
There are simple and complicated ways to wire them up.
Look at this link to see the different ways to connect them.
Delco SI Alternator 1-Wire vs 3-Wire Explained
Dave M7040

Your alt. wiring link is nice & very informative but won't help when it comes to installing a 12 volt alternator on a 24 volt system.

 

[CraigM]

Tex: I'm not doubting your credentials or knowledge of the parts catalog, but when I look at the parts catalog or your picture of it, I see that they have delco 24v alternator listed for that short run, and I don't see any footnote at the bottom of the page. If that short run was for 12v conversions, why is the alt listed as 24v? Wouldn't it be listed as 12v?

Dave: My alt says delco 12v but according to the guy at Delco, it's not stock. Mine has 2 output terminals, neither is connected to the case. Look at the picture I posted. It is either a special that the guy at Delco has no documents about, or it has been field modified. The guy at Delco thought that it would be possible to do some electronic trickery and cause the thing to make 24v, but has no info on it. The info in your link may or may not apply. It does show how to hook up the terminals in the side of the alt, so that is of some help.

Looks like I've about exhausted everyone's thoughts, so here's a summary of the problem:

it's a JD5020 with 24v starter. By the serial No. it should have a 24v Motorola alternator. It actually has a delco alt that is marked 12v, BUT, the alt. is not stock. It has been modified. It has 2 output terminals and neither is connected to the case. The case can not be used as ground as in a conventional alternator. Given the neatness of the mod, I'd guess that it was done by either by Deere, or Delco, but Delco has no record of such a thing. (Tex, this would have happened during your parts tenure, does it ring any bells? did Deere modify them? Was there an aftermarket kit?) The alt was hooked into a very hacked up electrical system, so it is reasonable to assume that it did indeed make 24v and charge the 24v battery, but there is no way I can confirm that or even trace any wires ,there's not enough left. There is no evidence of any type of series/parallel relays or any other such thing that would explain a 12v alt.

If anyone can explain what I actually have, I'd love to hear it. Otherwise, I'll take my best guess, hook it up (12v at first) and hope for the best.

Thanks to all for the suggestions and ideas

 

[pmsmechanic]

I would take it to my favourite rebuild shop and have them spin it over. He would be able to tell me what is going on with it.

It would be interesting to take it apart and see how the circuitry is set up inside and there might be further clues written on the voltage regulator. It's a long shot but you never know what you would find inside. Good luck.

 

[Tx Jim]

Tex: I'm not doubting your credentials or knowledge of the parts catalog, but when I look at the parts catalog or your picture of it, I see that they have delco 24v alternator listed for that short run, and I don't see any footnote at the bottom of the page. If that short run was for 12v conversions, why is the alt listed as 24v? Wouldn't it be listed as 12v?

There was a short run(engine serial number 005574-007999) of supplying a Delco 24 v alt part number AR34567 . Here's what the footnote I referred to resembles on my computer. It's outlined in blue. I also included a photo of the parts descriptions which refer to the footnote. In reference to your alt modification I can't remember JD performing any mod's such as you suggest. My guess some shade tree mechanic or tractor owner installed it. I still think easiest & best thing to do is change 5020 over to 12 volts and be done with the 24 volt system. From yrs of diagnosing 24 volt system problems I dislike JD's 24 volt system. I know if it was my tractor that's what I'd do.
Jim