Tue Mar 13, 2012 2:21 pm
I bought a 1949 Farmall H last week. The previous owner's son said that the tractor would not charge a battery, so his dad always kept a spare charged so he could swap them out when necessary. The tractor switched to a 12 volt system years ago using a Delco Remy 12v Generator. I have a ballast resistor in front of the 6 volt coil, but other than that it is a positive ground 12 volt setup. I have searched all over the web, and can't find anybody with this scenario to tell me if my wiring is correct. I know just enough about electrical things to get me in trouble, and I'm having a hard time figuring out where the problem is. I have completely rewired the tractor with my wiring diagram attached in pdf form. The tractor runs great, lights work, everything's great, but I don't know if the battery is charging or not. Again, due to my ignorance on how to figure this out, I've tried several ideas, but none have given me a concrete answer either way. When I remove the positive (grounded) battery cable while the engine is running, it dies. If the generator/regulator were functioning properly, wouldn't it keep running without the battery in the loop? I disconnected the wire from the batt tab on the regulator, and measured voltage from the batt tab to the negative terminal on the battery and got 6 volts. That doesn't seem correct. I then measured from the negative battery terminal to the Arm post on the generator and got 14 volts. Is my regulator malfunctioning? How do I test it? I know I have my ammeter hooked up backwards, because if I turn on the lights without the engine running it tells me that the system is charging. I have yet to see the needle go in the opposite direction. I'm at a point where I need to figure out what isn't functioning properly in order to know what to replace. I hope that someone can give me some advice in regards to this. Thanks for any input.
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Tue Mar 13, 2012 4:02 pm
The only mistake I see in your wiring diagram is that the coil is wired backwards. That won't affect the charging circuit though.
From your voltage readings it sounds like the generator is not working.
The readings you want to take are from the generator A terminal to ground (battery +) not from the A terminal to battery - .
Measure the voltage across the two battery terminals with the tractor off. Then start it and run the tractor at mid to high idle and see if the battery voltage has increased. If the voltage is the same, run a jumper wire from the generator F terminal to ground. This bypasses the regulator and if the generator is good the voltage output should go up. If it is the same, the generator is not working or it may have a poor ground.
Have you polarized the generator?
Wed Mar 14, 2012 12:42 am
I did polarize the generator. I will try your recommendations tomorrow. I had planned on trying them tonight, but unfortunately an incident with our hot water heater, and I got to spend the night removing the old lime filled water heater, and replacing it with a nice expensive new one. The best part was that the water heater is in the attic.Anyway, as far as the coil being wired backwards, I drew it incorrectly, I do have the positive terminal of the coil connected to the distributor. I'm guessing that the "L" terminal on the voltage regulator is not necessary in my application. I'll update tomorrow when I have a chance to measure the voltages more accurately. Thanks for your help.
Wed Mar 14, 2012 11:55 pm
water heater in the attic???? Thats the first time I heard that one>>>>Better water pressure??? Kevin
Thu Mar 15, 2012 8:26 am
Nah, we live in Texas. Unfortunately people down here think that water heaters and blower units should be out of the way in an attic rather than in a closet that takes up floor space. I grew up in Ohio, and never heard of such a thing either. Anyway, I was able to take some readings on the system, and I believe that Bigdog's assessment is dead on with the generator being bad. I had left my ignition on all night two nights ago, so the battery was completely discharged by yesterday morning. I charged the battery and had the chance before work this morning to go out and take some readings though. The battery measured 13.2 volts before starting, and the same once it was running. I jumped the F terminal to ground and the voltage didn't move. I measured from ground to the A terminal on the generator and got 1 volt. I have a feeling I'll be headed to the starter shop in town to see about rebuilding my generator. Hopefully the voltage regulator won't need to be replaced after this... Is there any way to check the regulator before I get the generator rebuilt to see if it is ok? I'd hate to pay to have the generator rebuilt only to find out I need a $50 voltage regulator. I know a lot of people frown on alternator conversions, but this is a work tractor. I'd definitely keep the generator if I ever did switch to an alternator just in case I wanted to go back to a stock look. My main objective right now is to get the system completely operational with as little effort and money as possible. Thanks again for any opinions/suggestions.
Thu Mar 15, 2012 10:21 am
dilbone56 wrote:Nah, we live in Texas. Unfortunately people down here think that water heaters and blower units should be out of the way in an attic rather than in a closet that takes up floor space.
That is just one of the strange ways houses in Texas are built. Another one is to put pipes in the outside walls, as if it never gets below freezing. Then when cold weather is expected, they tell everyone to let their water faucets drip, as if we have water to just run down the drain!
Thu Mar 15, 2012 10:34 am
dilbone56 wrote: Is there any way to check the regulator before I get the generator rebuilt to see if it is ok?
Unfortunately, most of the test procedures assume you have either a bad generator OR a bad regulator and are trying to isolate the problem between the two. I have't seen one for testing a regulator when the generator is bad. As I think about the problem, here are some ideas, others posters may be able to confirm or refute.
1) Disconnect both wires between the generator and regulator, leave the "BAT" connection in place.
2) Check resistance between the regulator "F" terminal and ground. On a regulator it should read 0. On a cutout relay it should be between 1 and 2 ohms.
3) Check resistance between the regulator "GEN" and "BAT" terminals. It should show an open circuit.
-- a) Measure voltage at the battery.
-- b) Connect your battery charger to the "GEN" terminal of the regulator, the same as you would normally connect it to the battery and turn it on.
-- c) Measure voltage at the battery and at the "GEN" terminal where the charger is connected.
-- Both readings should be very close to the same and above the battery voltage measured at step 4 a.
Anybody think this makes sense?
Thu Mar 15, 2012 12:39 pm
Jim - I believe those procedures will work.
Thu Mar 15, 2012 3:56 pm
Jim, Thanks for the input. I will definitely try those tonight. I called our local starter shop today, and they estimate my generator will run $95-125 to rebuild. I'm going to run these tests you mentioned, and if the regulator checks ok, I'll dig in to the generator to see if I'm lucky and it only needs a good cleaning and brushes. Otherwise I've already purchased my backup plan. I went to O'Reilly's and bought a delco 10si. Out the door remanufactured for $60. If all else fails I'll be switching the polarity on my battery and coil, and going with a one wire setup from the alternator. Hopefully someday soon I'll be mowing some road frontage and grading my yard. Good thing I'm better with mechanical items than electrical ones. Otherwise I'd be posting about my engine too. Thanks for all the help guys. I'll post a final result as soon as I know.
Thu Mar 15, 2012 9:44 pm
Well, I have bad news, good news, then more bad news. I tested the regulator, and according to the directions above the resistance between the F terminal and the ground was 19 ohms, however between the "GEN" and "BATT" tabs did show an open circuit. The voltage at the battery was 12.8v. Then I connected my charger to the "GEN" terminal and the ground and the charger kicked on and off, but the voltage never rose above 12.8v. So I'm thinking at this point that the generator and the regulator are both bad. I then fabricate a make shift bracket out of extra parts I have around the shop and I mount the alternator. It took me a few minutes, but I wired it up. Follow my logic here and tell me if anything is wrong. I first disconnected the battery. Then I took the wire from the "BATT" terminal on the regulator and placed it directly on the "BAT" terminal on the alternator.I removed the wires that went from F to F, A to GEN, and removed the voltage regulator. Then I switched the terminals on the coil, and finally switched the battery cables. As I had said in an earlier post, the ammeter has been hooked up backwards, so I know that now it will be proper. The tractor fired right up, and ran great. However my ammeter was showing a 2 amp load on the system. I increased the engine speed and initially the current load went up, then back down to 2 amps. When I turned on my lights I got a 10 amp load on the system. I measured the voltage across the battery and it was no higher than when the engine wasn't running. What the heck? I have a simple, single wire system, and still no charging. I disconnected the wire from the alternator and measured the voltage from the terminal to ground and got nothing. Shouldn't I have at least 13 to 14 volts here? I am at a loss. I removed the alternator and am taking it back to O'Reilly's tomorrow to have them check it, other than that I don't know what could be going wrong. When the engine is running and the alternator is hooked up, I get 12v from the bat terminal to the ground, but that's from the battery.
edit: I forgot to mention that I also disconnected the negative battery cable while the engine was running just to verify the alternator wasn't putting anything out, and the engine died.
Fri Mar 16, 2012 11:52 pm
OK, success finally. I forgot to run a wire from the ignition switch to the #1 tab on the alternator. So, I ran a wire from the switched side of the ignition switch to a 12v light, then from the other wire of the light to the #1 tab on the alternator. Then a jumper from the #2 tab to the Batt tab on the alternator. I'm finally getting over 14 volts while the engine is running, I can also disconnect the battery and the engine keeps running. Finally. The issue I have now is that the indicator light never turns off unless I turn off the ignition. I guess because there is a minimal voltage difference from the battery to the alternator it stays lit. Any ideas? Do I necessarily need the light, or can I just run a straight wire from the ignition switch to the alternator #1? Any help would be very much appreciated. I'm so close to having this thing the way I want. Oh, and by the way, I hate to change the subject but I am out of adjustment on my engine speed linkage, and I am only running at 1400 rpm with the lever maxed out. Is there another adjustment that I am not seeing? Maybe inside the governor? Thanks again for all of the help guys.
I just realized, I placed the ballast resistor before the ignition switch. This has to be why the indicator light is always on. There will always be a voltage drop there because of the resistor. I have to rewire it so that the resistor is after the switch, and separate from the wire with the light. I guess I just needed a little while to think about it. If anybody has anything they'd like to add or disagree with please let me know. Thanks.
Sat Mar 17, 2012 6:11 am
I guess it turns out that your alternator is not a 1 wire, but a 3 wire. It's no problem, you just need to know from the start. On a true 1 wire, neither of the small wires would have been required.
I'm confused by your question about your indicator light staying on unless you turn off the ignition, that sounds normal to me. One concern I do have, however, when the engine is running and alternator working, does the engine die, as it should, when the ignition switch is turned off? If not, you need to put a diode in line in the wire connected to the #1 terminal.
Sat Mar 17, 2012 6:49 am
So the indicator light is going to stay on whenever the engine is running? I was under the impression that the light would turn off once the alternator started charging. To answer your question Gary, yes, when I turn off the ignition switch the engine dies. I think what I may have said that was confusing was that I can remove the battery from the system while the engine is running, and the engine will stay running. This, is my one true way to convince myself that the alternator is operating properly. Sorry for the confusion.
Sat Mar 17, 2012 8:15 am
OK, now I see. When the alternator stars charging, the light should go out as you expect it to. If it's for sure charging, there's a problem with the alternator, perhaps you've popped a diode in your trying to get it to work. That also explains why the engine shuts down properly. If the alternator were working right, it would back feed to the ignition system and prevent shutting the engine off, hence the diode I mentioned previously.
Please stop removing your battery cable, to check for charge. Electronics are sensitive to the very high voltage spikes this practice can cause and may well be the cause of the problem you now have.
Sat Mar 17, 2012 4:57 pm
Understood, I will not remove the battery cable. Actually I only tried it twice. Once and it the alternator wasn't charging, and the second time it was. I actually figured out what was going on this morning. When I wired the tractor, I placed the ballast resistor in front of the ignition switch. Since the only item I had running from the switch was the coil, it worked better for me that way, because physically it allowed me to place the resistor in a more discreet area. However, I had forgotten this little fact when I connected the light to the ignition switch. Basically, I had the resistor in front of the indicator light. Which kept a constant voltage difference across the bulb, hence the constant light. I have since rewired it, and everything works exactly as I had expected it to. When I first start the tractor, the light stays on and the ammeter shows a minor discharge until I have increased the engine speed to about half throttle. Then the light shuts off and the gauge instantly shows a charge. I can then decrease the engine speed and do whatever I need while it keeps charging the entire time. Exactly what I wanted. Now I just need to figure out this engine speed thing. Thanks for all of the advice.
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