Delco 10 SI question

[ole fred]

Does anyone know how to test a 10SI to see if the regulator is working without mounting it on a tractor?
I have several that I have no idea if they work. I hate to mount them on the 641 to test them as I have to replace the pulley on each.

 

[used red MN]

Does anyone know how to test a 10SI to see if the regulator is working without mounting it on a tractor?
I have several that I have no idea if they work. I hate to mount them on the 641 to test them as I have to replace the pulley on each.

Take the alternator to a parts store and have them test it. You will still need to put a pulley on it. What’s hard about that? Impact wrench, blapp.. done.

 

[old]

Does anyone know how to test a 10SI to see if the regulator is working without mounting it on a tractor?
I have several that I have no idea if they work. I hate to mount them on the 641 to test them as I have to replace the pulley on each.

Most auto parts stores will test them for free in hopes of selling you one

 

[ole fred]

I know, I can do whatever a parts store can do. I can change a pulley also, but I was hoping there was a way to use a VOM to maybe just check continuity or something. I have probably 40 of the 10DN's and 10SI's lying around. I collected them years ago and used the 10DN's on my White Freightliners. They are simple and foolproof.

 

[used red MN]

I know, I can do whatever a parts store can do.

But do you have the equipment to do it? Very likely no.
Here is a link to a video of how to test them. You will need a DC power supply that you can vary the voltage output between 12-16 volts to perform the test.
10SI Regulator test

 

[Jim.ME]

I don't have it in hand to post however there is info available online on testing the Delco alternators. However, I am thinking to test one without the alternator being run you are going to break it down into components and test each one as if doing a rebuild. It is likely quicker and easier to pick a unit with easy access to the alternator and install a pulley, mount, and run them to test.

 

[ole fred]

This is getting way more involved than I thought it would. I was just hoping someone could say that, Yeah, if you have continuity from here to there, the regulator is probably good.
As for taking it to a parts house to get IT checked, yeah, I could do that but I'm not going to carry a five gallon bucket of them in and ask to find me one that works. Not my style.
FWIW, I used to buy cores at the local NAPA store maybe 40 years ago. The 10DN's were fifty cents. The 10SI's were maybe a dollar. As for the 10SI's, they were probably there because the regulators weren't working.
As any rate, I'll get something going - probably a 10DN though.
Thanks for all that commented.

 

[KCTractors]

I was told if you hold a screwdriver on the opposite side of the pulley side on the alternator and if it holds the screwdriver that the alternator is working. If that's right I really don't know for sure.

 

[Hobo,NC]

This is getting way more involved than I thought it would. I was just hoping someone could say that, Yeah, if you have continuity from here to there, the regulator is probably good.
As for taking it to a parts house to get IT checked, yeah, I could do that but I'm not going to carry a five gallon bucket of them in and ask to find me one that works. Not my style.
FWIW, I used to buy cores at the local NAPA store maybe 40 years ago. The 10DN's were fifty cents. The 10SI's were maybe a dollar. As for the 10SI's, they were probably there because the regulators weren't working.
As any rate, I'll get something going - probably a 10DN though.
Thanks for all that commented.

Its very rare to see a bad regulator in a 10si. 80% of the issues were DIODE TRIOS, 10% bad rectifier, 5% a brush issue, 3% a bearing and 2% a bad stator are the extremely rare rotor issue. I doubt you would find 1in a 100 with a bad regulator.

 

[ole fred]

IIRC, there is a small hole on the back side that you can insert a small screwdriver or such into and ground the inside tab to the frame and it will bypass the regulator and make the alternator charge. That will tell if the alternator is bad. If after grounding the tab the alternator it charges, but stops when you unground it, the regulator is bad, but the alternator is probably good.
I'd forgotten about that.
Still, in my case, I'd still have to mount it and that isn't an easy job.
Thanks

 

[ole fred]

Its very rare to see a bad regulator in a 10si. 80% of the issues were DIODE TRIOS, 10% bad rectifier, 5% a brush issue, 3% a bearing and 2% a bad stator are the extremely rare rotor issue. I doubt you would find 1in a 100 with a bad regulator.

Interesting. My experience is mainly with the 10DN's. I just finished "rebuilding" two that are "good as new"??. It took maybe 6 or 7 to satisfy me. Most were just dirty and corroded from lying around here for 35 or 40 years. Several had the terminals that hold the diodes and stator together twisted off or spun on the frame. No biggie. I have more. I only found two bad diodes. In my past, it seemed like the stator corroded. That and the front bearing went dry. Naturally, the brushes wore out, but I never saw one where the alternator quit because of that. When they are run in a Freightliner, the get wet often.

I had a diode go bad on the alternator in my 93 Chevy pickup and it "sang" and wouldn't put out full output.

While we're at it, the reason I don't like mounting one on the 641 is that the fan belt is just barely long enough to hold the alternator away from the governor control rod. When I put the alternator on, the lower bolt has to go through right where the belt is. It can be done, but it isn't easy. I've thought about putting the bolt in from the back side, but prefer to not have threads in the front bracket where all the tension is. It's probably not a big deal, but I'd just rather not.

Another thing: I used to buy 72 amp stators from LaFountaine Generator Exchange for $12 new. I still have a couple of new ones with several good as new. Also, I got Transpo regulators for $12. I can't say enough good about the place. It's an old time generator repair shop. LaFountaine, IN. North of Marion and south of Wabash on SR 15.

 

[john in la]

While a simple multi meter will have a diode check spot on the dial I don't think you can do a at home diode trio test unless you remove it from the alternator so a at home test is pointless.

 

[Russ from MN]

I just tested one last week, I ran a belt from my table saw motor to the alternator. I had it hooked to a battery, once I exited it the voltage went to about 14. Next summer it's going to be on our Farmall C!

 

[kencombs]

I just tested one last week, I ran a belt from my table saw motor to the alternator. I had it hooked to a battery, once I exited it the voltage went to about 14. Next summer it's going to be on our Farmall C!

I was just thinking about that, my first battery charger was an electric motor and alternator on some angle iron pieces. Also served as an alternator test stand. a couple of bolts and it was swapped. Easy, especially because it could be sitting on the bench.

 

[ole fred]

I was just thinking about that, my first battery charger was an electric motor and alternator on some angle iron pieces. Also served as an alternator test stand. a couple of bolts and it was swapped. Easy, especially because it could be sitting on the bench.

I had/have something similar. I made it as a test stand. It has a volt meter and an ammeter. I put a 1/2 horse 3450 rpm motor on it and excited it. It would kill that motor instantly. I don't remember what I used it for. I'm sure if I regulated it down to something reasonable, the 1/2 horse would handle it.

Hmmm. I wonder how many amps a half horse motor would produce. I'm sure someone could figure it out theoretically.