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Still messing with S/G


Brucep

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I wrote a while back and got some good info on Starter Generators from Edens Ltd, at the time mine had to have the armature replaced and they aren't cheap. Anyway, I ran threw the test that he sugested for trouble shooting after I got mine back on the tractor because the tractor wouldn't start after it sat a couple days and I figured it would be a great time to learn. This is what I came up with. With the engine at idle I had 16 volts at the A terminal and more volts at a little over half throttle. Should have been 13 to 14.5. The next step I didn't need to do because I had high voltage, but I wanted to see any way. So, I grounded the F terminal and got 17.4 volts. That was at idle also. The voltage at the battery was not within .1 or .2 of the voltage at the A terminal, it was higher. Then just to see what I would get I disconnected the S/G unit and measured the resistance between the F and A terminals and I got 8 ohms which is good. Atleast by the write up. I did replace the wire from the F terminal to the regulator. Test results are after that was done. My first thought is bad battery but when I did this test it kinda looks like the voltage regulater cut out section. There you have my dilema (sp) Battery, Voltage regulator or S/G still? Which one is bad? The battery holds a charge for the day. I'm able to start and stop the engine all day. But dead after a day or two without a start. Well, not dead but only has about 7 or 8 volts in it. Wont start the tractor. Looks like the S/G is doing it's job but the test results have me questioning. Probably an easy one for some of you but sure has me thinkin. Thanks all!
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----"With the engine at idle I had 16 volts at the A terminal and more volts at a little over half throttle. Should have been 13 to 14.5. The next step I didn't need to do because I had high voltage, but I wanted to see any way. So, I grounded the F terminal and got 17.4 volts. That was at idle also." From what you said here the SG is functional since you're getting voltage greater than battery voltage out of it. ----"The voltage at the battery was not within .1 or .2 of the voltage at the A terminal, it was higher. I'm not clear on this. With the motor running, place the red lead of your volt meter on the SG A terminal. Place the Black lead on the Battery (+) positive terminal. You should read approximatly .1-.2V here. You should read 13.5V or so with your voltmemter (-) to battery (-) and voltmemter (+) to battery (+) If the voltage above is actually .1-.2V, then you need to check for a short or a bad battery. After you're done, disconnect the battey and leave it off until the next time. If it starts, you're battery is fine. If not...time to go checking for shorts/drains.
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Bruce try disconnecting BOTH leads from the battery and see if it holds enough charge to start the mower after two or three days. If not, try another battery as that one is likely bad. If the battery proves good, try pulling the negative lead only and see what happens after a couple of days. If the battery holds up for that test start looking for a short to ground that is drawing off current while the tractor sits unused. It could be in the ignition switch,points or ignition module, voltage regulator or some other componet.
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Bruce, I suspect the battery. The 17 volt indicates either the regulator cut out is not working or the battery has a very hi internal resistance. The fact that it works and goes down in a day or so makes me suspect the battery, unless there is something connected that we aren't aware of. I would remove the battery cable when y ou park it and in a couple of days put the cable on and try to start it. If it doesn't work then, it has to be the battery as it is going down with nothing connected to it. Let us know what happens. Good luck, Al Eden
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What does the battery smell like after running the tractor for a while? If it has a vile smell, the battery might be bad. Is the battery warm after running the tractor for a while? If so, the battery again might be bad.
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Thanks everyone. I suspect the battery also, it was just the 16 plus volts at idle and half throttle and then the 17 plus volts with the F terminal grounded that had me wondering. I will unhook the battery for a couple days and see what I come up with. Paul, yes it does look like the S/G is functioning but the question or one of the questions is. Is the voltage regulator cut out section working? I'm not positive on this but I believe when the voltage regulator see's that the battery has gotten all of it's juice back it should lighten the load on the S/G. I think you are correct that the battery should read 13.5 or so but it should read within .1 or .2 + or - of the previous reading at the A terminal. I believe? If this is not correct I'm sure someone will let me know. There a pretty good bunch on here. My battery was reading good voltage, just not within .1 or.2 of the previous test reading. I haven't noticed any smell from the battery or that it was getting hot. I'll keep ya all posted on what I come up with but it mite be a couple days befor I'm able to get back to it. Thanks!
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if you have a test light take the pos cable off and clip on to the pos post and connect other end of light to pos cable. with everything turn off. if the light burn then there is a draw on your battery . leave light hook up and start disconnecting stuff like reg , s/g any electic. watch light as you disconnect if light goes out then you have found your problem. JJ
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quote:
Originally posted by Brucep
.... Is the voltage regulator cut out section working?.....
Your regulator cutout is working. When you ground the F terminal you are bypassing the entire regulator and the S/G is putting out the maximum it can (17.4 volts). Without the F terminal grounded your S/G is "only" putting out 16 volts because the battery is bad. Think of your battery as a water bucket and your S/G as a water pump. When the bucket is full the pump shuts off. If the bucket has a leak the pump just keeps running to try and fill it up. Even a premium battery usually lasts only a few years. A small garden tractor battery may last only one year. How old is your battery? A bad battery can cause all sorts of electrical problems and cause other components like the S/G, regulator, and even the wiring and connectors to burn up from being overworked. Replace that battery.
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One good way to test a battery is with a hydrometer. All the cells should be pretty close to each other in specific gravity.
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Gotta love all this good advice, it's great! Yep, if I need to I will test the circuts to see what's drawing. Lucky for me there aren't to many things to test in this old tractor. I'll see if the battery goes dead with nothing hooked to it first. Back to the S/G now. So the way I am understanding this when the cut out is working it will just prevent the supply of elctric from going to the battery like a switch therefor you see the full output of electric at the S/G because nothing is pulling on it, but when something is pulling on it you see less output. Like water pressure going to a fauset. Faucet open, less pres at the pump. Faucet closed, more pres at the pump because the pump is dead heading (which will make the pump hot) unless it is supplied with bypass or recirc. Correct? EXCEPT, with electric circuts, OPEN stops the flow of electric and CLOSED lets the flow of electric continue. This concept I understand. I just didn't know if the S/G actually backed itself down when the battery was up to par. It looks to me now that the voltage regulator kind of act as a switch to let electric flow or stop the flow. The S/G fields are allways excited. Wow, is that a mouth full or what?
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quote:
Originally posted by Brucep
Gotta love all this good advice, it's great! Yep, if I need to I will test the circuts to see what's drawing. Lucky for me there aren't to many things to test in this old tractor. I'll see if the battery goes dead with nothing hooked to it first. Back to the S/G now. So the way I am understanding this when the cut out is working it will just prevent the supply of elctric from going to the battery like a switch therefor you see the full output of electric at the S/G because nothing is pulling on it, but when something is pulling on it you see less output. Like water pressure going to a fauset. Faucet open, less pres at the pump. Faucet closed, more pres at the pump because the pump is dead heading (which will make the pump hot) unless it is supplied with bypass or recirc. Correct? EXCEPT, with electric circuts, OPEN stops the flow of electric and CLOSED lets the flow of electric continue. This concept I understand. I just didn't know if the S/G actually backed itself down when the battery was up to par. It looks to me now that the voltage regulator kind of act as a switch to let electric flow or stop the flow. The S/G fields are allways excited. Wow, is that a mouth full or what?
Whew....... I don't know??????? Since you're now working on your S/G, this would be a good time to take a few minutes and read Al Eden's excellent article. > http://www.simpletractors.com/service/electrics/electrical_systems.htm Very basically, the regulator "watches" the battery and other electrical current demands of the system and "tells" the generator how much electricity to generate. With the engine running...... If you remove the wire from the F terminal, the generator will be turning but it won't be producing any electrical current. If you connect a ground wire to the F terminal, the generator will produce electricity to it's maximum ability until it destroys the battery (cooks it), burns out light bulbs, wires and anything else OR until it burns itself up (whichever comes first). The regulator simply keeps grounding and un-grounding the F terminal automatically in safe short spurts.
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Ok, that's a good article. That's where I got the info to do the test but I don't remember reading that. Electric seems hard to follow cause you can't see it and if you could it all happens so fast. I asked an electrician a little bit about a 150 mega watt generator when it was being rebuilt. He talked a little and when he was done he said it's like magic.
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Bruce, there is no magic to electricity. When you consider the fact that it has been studied and controlled for over 2000 years, it becomes a bit more friendly. Think about the S/G unit you have. It is old technology, over 80 years old. Keep studying it and each day you will get to know more and more about it.
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Well, it looks like it's just the battery. I unhooked it and it still looses it charge. So, mistery solved. It is about two years old if I remember right and it wasn't a real exspensive one. Thanks everyone for all your help and suggestions!
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Please remember to refill a low battery only with distilled water. Minerals in regular water can be fatal to a battery. Also, if you add battery acid, when the acid level is low, that will not be a good thing for the battery.
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