Hi everyone, I haven't posted in a long while but the last time I was here I got so much great information from a lot of people. I've got another problem so I figured I'd ask for help here again. I have a Case 350 track loader with a case 188 4cyl diesel. It used to have a generator but it was replaced about 30 years ago with a delco si 3 wire alternator that was never hooked up correctly so it never charged, which wasn't a huge problem because it has 2 batteries and zero electronics, the headlights were broken a long time ago. Well last weekend the vbelt broke so I figured while I was at it, I'd replace the alternator, wire it up to work, and wire some new led headlights. So I ordered a new GM SI internally regulated 63amp 3 wire alternator, some wire, a new ammeter, and an indicator light. I watched a ton of YouTube videos and studied a bunch of 3 wire alternator wiring diagrams. I mounted the new alternator, ran a wire from a 12v key on circuit, to the idiot light, to pin 1 on the alternator for the excite circuit. Then I ran pin 2 directly to the battery output on the alternator. And finally I ran a thick wire from the batt output to the positive post on the starter solenoid. Following the attached diagram exactly. (I haven't hooked up the ammeter yet, I just wanted to make sure the alternator would charge) I start the tractor and check across the battery terminals with my meter...nothing. 12.03v. The idiot light is on but dim. I hold a wrench up to the back of the alternator and I can feel a strong magnetic field. When I unhook the thick charging wire from the battery and check it with my meter I get 14v but as soon as I connect it back to the battery positive I get zero charging. I've tried running the charging cable to the starter and to the battery. I added a grounding cable from the alternator to the engine block and still nothing. No matter what I do I get 14v with the charge wire unhooked and 12v with no charging with the charge wire connected. Has anyone ever seen anything like this? I'm not sure where to go from here.
I'm no expert on alternators, but I think I'd toss that three wire system and simply put a Delco 1 wire on it. And I'm not fond of Amp meters at the instrument panel, that requires a heavy gauge wire from the Alt, to the gauge, then back to battery. A volt meter gives just as good information and only requires like a 16 gauge wire.
What rpm, just checked at idle, some three wires need the rpm to hit 1000 plus before it starts charging, have a forklift in the shop with a three wire that has to see some R's.
I've seen that happen before. Had a customer that fitted an automotive (gas engine) alternator on a Deere 4239 diesel, wouldn't charge at idle. Fitted a slightly larger diameter pulley on the alternator and fixed the problem. Diesel engines run at a lower rpm than gas engines, generally speaking.
Not sure why the jumper to terminal 2. Should work without that. But definitely agree, go with the 1 wire. It will either work or not. . .
I actually tried a Delco 1 wire alternator first. I bought a 120amp, delco 10si, self exciting, low rpm turn on alternator. I ran an 8 gauge cable from the output terminal on the alt to the positive cable on the starter solenoid. Nothing. It wouldn't charge no matter how high I revved the engine. The paper that came with the alt said it turned on at 1400rpm. According to Google the case 188 engine has an rpm range from 600 to 2100 (the tach used to run off the generator so this tractor no longer has a tach). I figured the engine just didn't spin fast enough to start the one wire alternator so I bought a 3 wire alternator since the key on circuit is supposed to turn on the alternator regardless of rpm.
Have you got a ground wire going from the frame to the engine? If that engine doesn't have a good ground then nothing electrical will work as the engine is isolated on rubber mounts.
On second thought, then the starter wouldn't work. I'm baffled.
The engine pulley is quite a bit bigger than the alternator pulley, so it should have turned on the one wire when you revved it. Did you start with charged batteries? might be as simple as nearly dead batteries and not much amperage at idle. Is the idiot light an LED? might not flow enough amps to excite the alternator, but seems like it is, check the voltage at #1 terminal when hooked up and running. You could try anything conductive in the test hole to short the tab to the case, looks like the oblong hole just to the right of the shaft in that pic, that bypasses the voltage regulator and goes to full output. I'd run it an hour and then check the voltage again, might just need to charge the batteries to get the voltage up.
Two batteries? I'm not gonna assume so I'll ask. 12v or 24v?
Willie59, didn’t you mean to say ‘smaller’ pulley on the alternator so it would turn a bit faster?
The idiot light is led, although I've bypassed it and ran a test wire directly from the battery to pin 1 with no change. My batteries are not in the greatest shape and they're actually pretty dead at the moment, I've been using a jump box to start the tractor. I'll throw the charger on in the morning and see if full batteries make a difference. Two 12v batteries hooked up in parallel for a total of 12v still.
Good on the 12v. Might ought to charge with a "good" charger, not one of the idiot box new ones....
I threw away all of those "smart chargers", worst things ever invented. Schumacher seems to be the only company that still makes reasonably priced manual battery chargers, I bought a couple of them.
10 ohm, 10w resistor or something like a #194 bub on the #1 indicator terminal, I recall. But, if you full field it with a paper clip and nothing happens, maybe the new alternator has a problem?
Generally voltage is a better measure than amps, but you may have found the exception. If your batteries are completely dead, as in a dead cell in each, then they could show that low of voltage even though they're charging. Easiest to have a battery sitting at 12.7 then you know what's going on. Another possibility is bad diodes, that could cause the alternator to show magnetism, but not put out amps and volts to specs.
Well I charged the batteries for a little over an hour, voltage showed 12.8V and the tractor started right up but still no charging. I took some pictures to show what I'm working with. I just have everything hooked up temporarily, I wanna make sure I can get everything to work before I start installing stuff for good. My red indicator light is always on with the engine running. I have batt voltage going into the light but only 9.1v-10v going to pin 1. But even when I bypass the light and apply 12v to pin 1 it still doesn't charge. I have the wrench stuck on the back of the alternator to show that it is creating a magnetic field. I dont know....maybe I'll take the brand new alternator out and have Autozone test it. It really seems like this setup should work.
I put a 10si on a 310 John Deere last summer using the diagram below and it worked. I had to rev the engine up a fair bit to get it started. Where is the second wire from the charge light going at the left of the bottom picture? Also I think a LED may not have enough load for it to charge.
One issue--the electrical parts end is terrible--the amount of poor quality is off the charts.
But, it says right on the unit, “ triple tested”.
So, since the rotor is magnetized, there isn’t much stopping the unit from charging. Maybe the diode trio accidentally got zapped? Maybe the B+ wire shorted out to something? Maybe the B+ wire has a bad connection?
Well...I am the lord of the idiots. So when I replaced the v belt I replaced it with one of those Accu-link belts so I wouldn't have to pull the radiator, drain the hydraulic system, and unbolt the hydraulic pump from the crankshaft. Well those accu-link belts stretch a lot so I've been taking links out every time I run the machine. This time I noticed I could turn the alternator pulley by hand with the belt tensioned. Turns out I was trying to use a 3/8" pully with a 1/2" belt. So I swapped on the old pulley and pulled a few more links out of the belt and got it tensioned nice and tight. I started the machine and could see that the alternator was spinning faster. But it still wasn't charging and the idiot light was lit up bright red. I unhooked the light and jumped the terminals together and that was it. It's now charging at 13.8V I even hooked up one of my new led headlights and the voltage didn't drop. I'm just gonna eliminate that dummy light since this machine is turned off with a manual fuel shut off so I really don't care about back feeding on that circuit. Now I get to clean up all this wiring and install everything for good.
Something was learned today.
I was just checking the way I have the 10SI Delco Alternator on my 1947 Farmall BN. On mine the "Batt" terminal goes right to the "AMP" gauge then the other side of the "AMP" gauge goes to the "POS" terminal of the battery. Both spade terminals (#1 and #2) go to one side of a pressure switch and the other side of this pressure switch is connected to the "POS" terminal on the starter switch. Think I used a simple 10#(or maybe even lower) pressure switch. No idiot light in the circuit. It's been hooked up like that for something like 30 year, maybe more and is only on the second battery since I converted to 12 volts. And it was a used alternator, think it came off a old Chevy we scrapped at the quarry, when I did the conversion! This is a newer version of the switch I used:
Those Hobbs switches were used back in the day to open the circuit. It’s a feature of the creature, in the SI family, to have a 10-15 milliamp parasitic drain.
Got all of my permanent wiring in, installed my new headlights and used the ol girl today to pull some stumps out of ground and everything seems to be working just fine. My amp meter reads right around 10 amps or lower most of the time and those $20 Chinesium led lights draw almost nothing. I hooked up my voltmeter to the battery to watch the voltage...its not like a car where you get 14v instantly, I get a slow ramp up from 12.5V to 13.8V (im sure my junk batteries arent doing me any favors) but hey it's charging so I'm happy. I have an empty gauge hole so I think I'm also gonna add a volt meter just because that's what I'm more used to reading.
I bought a current shunt and remote meter from Amazon for about $50 can. for our camper battery. Gives both voltage and current and I only ran small wire to the meter. Cam