Might be a dumb question, but I have to throw it out.
In as much as so many of these machines have positive grounds, and the generator is pushing juice out the negative side to the battery, when using a battery charger with the cables attached, can it affect, or possibly reverse, the polarity of the charging system?
Simply put, should the batt cable be disconnected when the battery is being charged with a charger??
Gary
Question on polarizing
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Stan Disbrow
- 350 crawler
- Posts: 2898
- Joined: Fri Jul 15, 2005 3:13 pm
- Location: Raleigh, NC
Hi,
Are you were concerened about causing a 'ground loop' current flow? If so, then you don't have anything to worry about.
The case of the charger isn't attached to either the Pos or Neg output of the charger, so there's no association with which side of the battery is 'ground' and the case of the charger.
Now, the case of the charger *is* attached to the AC input 'ground', which is probably better off called 'earth' in this case. This is thru the AC line cord, of course. The crawler is certainly connected to earth, too, by its' tracks. I can see where you might be worried about there being a current flow from the charger to the machine thru the ground.
The transformer in the charger that converts the 120v AC to the appropriate lower voltage AC, which is then converted to DC thru a rectifier, isolates the output from the input. This, happily, lets you attach the proper output lead to the frame of the machine with no fear about causing a 'ground loop' current flow.
As Lavoy points out, as long as you attach the Pos cable from the charger to the Pos terminal of the battery (and Neg to Neg), you're OK.
Now, if you cross that up and hook Pos to Neg (and Neg to Pos), perpare to see a cloud of smoke rise up out of the charger!
I have at least six chargers around the place that I've repaired from the reverse polarization burnups. People like to give me toasted chargers for some reason.
Actually, modern chargers have a protective device that opens up the circuit should one get things crossed up.
Stan
Are you were concerened about causing a 'ground loop' current flow? If so, then you don't have anything to worry about.
The case of the charger isn't attached to either the Pos or Neg output of the charger, so there's no association with which side of the battery is 'ground' and the case of the charger.
Now, the case of the charger *is* attached to the AC input 'ground', which is probably better off called 'earth' in this case. This is thru the AC line cord, of course. The crawler is certainly connected to earth, too, by its' tracks. I can see where you might be worried about there being a current flow from the charger to the machine thru the ground.
The transformer in the charger that converts the 120v AC to the appropriate lower voltage AC, which is then converted to DC thru a rectifier, isolates the output from the input. This, happily, lets you attach the proper output lead to the frame of the machine with no fear about causing a 'ground loop' current flow.
As Lavoy points out, as long as you attach the Pos cable from the charger to the Pos terminal of the battery (and Neg to Neg), you're OK.
Now, if you cross that up and hook Pos to Neg (and Neg to Pos), perpare to see a cloud of smoke rise up out of the charger!
I have at least six chargers around the place that I've repaired from the reverse polarization burnups. People like to give me toasted chargers for some reason.
Actually, modern chargers have a protective device that opens up the circuit should one get things crossed up.
Stan
There's No Such Thing As A Cheap Crawler!
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
To Lavoy's point, hooking up a battery charge presents no problem so long as the polarities are correct. The only way that I could even conceive a problem is in a jump starting situation where you had two different crawlers with different ground polarities setting on a conductive surface, like wet salty earth. In that case, you've got a positive to negative connection through the earth and that would be a problem.
Not a real problem from my way of looking at it. If you like working with electricity when standing in water, best wishes and make sure it's easy to find your next of kin notification list.
Not a real problem from my way of looking at it. If you like working with electricity when standing in water, best wishes and make sure it's easy to find your next of kin notification list.
Bill Wattson
To all, Thanks,
I will have to work at digesting this. What little electrical theory I was taught in Air Force was a very long time ago.
I don't think, though, that the charging system is working. After installing the new regulator and gauge, and then polarizing the system, it did indicate a charge immediately after the first start up. There after, the needle appeared to remain neutral. Yesterday, it seemed to be leaning very slightly, and when under load, to the negative side. I have it charging, and will start properly monitoring the battery voltage for the next few work sessions. It starts quite easily, and probably is not using a lot of juice.
Gary
I will have to work at digesting this. What little electrical theory I was taught in Air Force was a very long time ago.
I don't think, though, that the charging system is working. After installing the new regulator and gauge, and then polarizing the system, it did indicate a charge immediately after the first start up. There after, the needle appeared to remain neutral. Yesterday, it seemed to be leaning very slightly, and when under load, to the negative side. I have it charging, and will start properly monitoring the battery voltage for the next few work sessions. It starts quite easily, and probably is not using a lot of juice.
Gary
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Stan Disbrow
- 350 crawler
- Posts: 2898
- Joined: Fri Jul 15, 2005 3:13 pm
- Location: Raleigh, NC
Hi,
Oh! you're talking about the on-board generator polarity becoming reversed when there's an external charger attached. I think. Now that I've read it all again....
No, I can't see where attaching a charger, even in reverse, would wind up reverse polarizing the iron plates inside the generator.
Firstly, you'd have to have the machine running to activate the cut-out relay in the regulator. With the machine off, that relay disconnects the generator from the battery, so there's be no current flow.
Secondly, even if the cut-out relay were stuck in the 'on' position, the charger would have to supply enough current to overcome the battery *and* supply the necessary current to the field coil in the generator to reverse the magnetic field in the iron plates.
I don't see that happening without a large amount of smoke issuing from the charger. Even if it's a huge charger, it'd make so much heat trying to reverse polarize the battery that the charger and/or battery would catch fire.
I guess that leaves us with the case where the battery isn't well connected for some reason *and* the cut-out relay is stuck 'on'. In this case, if you had a large enough charger connected in reverse, you could reverse the magnetic field in the iron plates. Seems unlikely that this happened, though.
What you can do, is attach a digital voltmeter to the battery terminals, then start the machine. Note the intial reading, then note the massive drop when you engage the starter. The battery voltage will rise slowly on it's own, but if the generator is charging, the voltage will rise rapidly. That'll tell you the true story.
Stan
Oh! you're talking about the on-board generator polarity becoming reversed when there's an external charger attached. I think. Now that I've read it all again....
No, I can't see where attaching a charger, even in reverse, would wind up reverse polarizing the iron plates inside the generator.
Firstly, you'd have to have the machine running to activate the cut-out relay in the regulator. With the machine off, that relay disconnects the generator from the battery, so there's be no current flow.
Secondly, even if the cut-out relay were stuck in the 'on' position, the charger would have to supply enough current to overcome the battery *and* supply the necessary current to the field coil in the generator to reverse the magnetic field in the iron plates.
I don't see that happening without a large amount of smoke issuing from the charger. Even if it's a huge charger, it'd make so much heat trying to reverse polarize the battery that the charger and/or battery would catch fire.
I guess that leaves us with the case where the battery isn't well connected for some reason *and* the cut-out relay is stuck 'on'. In this case, if you had a large enough charger connected in reverse, you could reverse the magnetic field in the iron plates. Seems unlikely that this happened, though.
What you can do, is attach a digital voltmeter to the battery terminals, then start the machine. Note the intial reading, then note the massive drop when you engage the starter. The battery voltage will rise slowly on it's own, but if the generator is charging, the voltage will rise rapidly. That'll tell you the true story.
Stan
There's No Such Thing As A Cheap Crawler!
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)
Stan,
My charger is quite small; perhaps one of the smallest. I bought it for my bike, but it will also do six volt, so I use it on the tractor. I have begun monitoring the juice in the battery, but I'm quite sure there is no generating going on. I will pull the unit, in the spring, and have it re-tested.
Thanks,
Gary
My charger is quite small; perhaps one of the smallest. I bought it for my bike, but it will also do six volt, so I use it on the tractor. I have begun monitoring the juice in the battery, but I'm quite sure there is no generating going on. I will pull the unit, in the spring, and have it re-tested.
Thanks,
Gary
You may want to try repolarizing the generator to see if it gets the generator charging again. This can be done by starting the engine and with a wire, monentarily jump across the "BAT" and "GEN" terminals on the voltage regulator. Do not be surprised if you get a large spark when you do this. Then check and see if the battery voltage is higher. If so, your generator is likely working. If not, it could be the generator, regulator, or both. Check on-line for bench testing a generator if you want to test it. It is pretty simple to test.
Jac,
If I understand correctly, you are saying that the engine should be running when the polarization is done? I didn't know that, but I will try it in the morning.
I'm still fighting an engine miss, too. I changed the filter. That didn't help, although the filter was considerably plugged. I then completely cleaned the carb. It's running well, but it's also raining well, and it was getting dark, so I didn't get a chance to test it under load.
Always seems to be something.
Thanks,
Gary
If I understand correctly, you are saying that the engine should be running when the polarization is done? I didn't know that, but I will try it in the morning.
I'm still fighting an engine miss, too. I changed the filter. That didn't help, although the filter was considerably plugged. I then completely cleaned the carb. It's running well, but it's also raining well, and it was getting dark, so I didn't get a chance to test it under load.
Always seems to be something.
Thanks,
Gary
Gary:
I polarized mine while running the engine. I had to install a new voltage regulator on my machine. Once I installed the new regulator, I simply started the engine and jumped across the BAT and GEN terminals. The shop I bought the new regulator from said to expect a large spark, which was exactly what I observed. Amp meter immediately when to full scale indicating the generator was putting out power. I had bench tested my generator so I knew it worked prior to putting everything together.
I polarized mine while running the engine. I had to install a new voltage regulator on my machine. Once I installed the new regulator, I simply started the engine and jumped across the BAT and GEN terminals. The shop I bought the new regulator from said to expect a large spark, which was exactly what I observed. Amp meter immediately when to full scale indicating the generator was putting out power. I had bench tested my generator so I knew it worked prior to putting everything together.
Jac,
Ok, I'll give it a try, but not until spring, I think. We are getting ready to pull out for a couple months in the desert southwest sun, and away from the cold and wet. I just put the cat in the shop.
I have been simply charging the battery everynight. It really doesn't use much power for 4 or 5 hours of running.
I finally had two days of operations without anything busting. I've moved a lot of dirt with it in the last week. It seems to run strong and well. There are a couple of things that will need addressing, but not immediately.
Thanks for the information. I hope it will make the meter jump when I do it. I would feel better if it were feeding itself, as it should.
Also, in one of my other posts, I had asked if I should, or should not, replace the little flapper on the choke plate. I've learned that I don't really need it. It starts without it, and serves no apparent purpose when warm and running.
Thanks,
Gary
Ok, I'll give it a try, but not until spring, I think. We are getting ready to pull out for a couple months in the desert southwest sun, and away from the cold and wet. I just put the cat in the shop.
I have been simply charging the battery everynight. It really doesn't use much power for 4 or 5 hours of running.
I finally had two days of operations without anything busting. I've moved a lot of dirt with it in the last week. It seems to run strong and well. There are a couple of things that will need addressing, but not immediately.
Thanks for the information. I hope it will make the meter jump when I do it. I would feel better if it were feeding itself, as it should.
Also, in one of my other posts, I had asked if I should, or should not, replace the little flapper on the choke plate. I've learned that I don't really need it. It starts without it, and serves no apparent purpose when warm and running.
Thanks,
Gary
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hunter41mag
- 440 crawler
- Posts: 126
- Joined: Tue Apr 12, 2005 7:11 am
- Location: Eastern Pennsylvania (NE of Allentown)
Gary,
If everything else is checking OK than do not forget about the ground side of the electrical components (generator, regulator, etc). I had our John Deere B driving me nuts because it was not charging. Everything was checking out OK and than I finally started to check the grounds. I found the regulator to generator mounting had a big voltage drop (bad ground). I removed the regulator, cleaned its brackets and generator mounting area, put it back together and it worked again. One of your posts said you installed a new regulator so its ground should be OK. Than check for voltage drop from generator frame to battery positive ground. If you have more than .2 volt reading (drop with engine running) than you have a bad generator ground.
Don
Eastern PA
440IC
If everything else is checking OK than do not forget about the ground side of the electrical components (generator, regulator, etc). I had our John Deere B driving me nuts because it was not charging. Everything was checking out OK and than I finally started to check the grounds. I found the regulator to generator mounting had a big voltage drop (bad ground). I removed the regulator, cleaned its brackets and generator mounting area, put it back together and it worked again. One of your posts said you installed a new regulator so its ground should be OK. Than check for voltage drop from generator frame to battery positive ground. If you have more than .2 volt reading (drop with engine running) than you have a bad generator ground.
Don
Eastern PA
440IC
Don,
I'm going to print this, and hope I don't miss-place it. I have the cat in the shop, and we will be leaving, soon, so I won't get back to it until spring.
I did, though, clean up all the grounding, or contact, surfaces on the generator. It should be well grounded, but one never knows.
Thanks,
Gary
I'm going to print this, and hope I don't miss-place it. I have the cat in the shop, and we will be leaving, soon, so I won't get back to it until spring.
I did, though, clean up all the grounding, or contact, surfaces on the generator. It should be well grounded, but one never knows.
Thanks,
Gary
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hunter41mag
- 440 crawler
- Posts: 126
- Joined: Tue Apr 12, 2005 7:11 am
- Location: Eastern Pennsylvania (NE of Allentown)
Gary,
I am not exactly sure what you mean by flapper on the choke plate?
If I am picturing it correctly I believe it allows a certian amount of air/gas through to the cylinders when the choke is closed completly. But in case of a backfire it closes to keep the gas in bottom of carb from catching fire.
So it's OK and nothing will happen until you have a backfire and than who knows the damage that may result???????
So if this is the purpose of the flapper on the choke plate than I would replace it.
Don
Eastern PA
440IC
I am not exactly sure what you mean by flapper on the choke plate?
If I am picturing it correctly I believe it allows a certian amount of air/gas through to the cylinders when the choke is closed completly. But in case of a backfire it closes to keep the gas in bottom of carb from catching fire.
So it's OK and nothing will happen until you have a backfire and than who knows the damage that may result???????
So if this is the purpose of the flapper on the choke plate than I would replace it.
Don
Eastern PA
440IC
Don,
The flapper may have been backward on my choke assembly. I assumed it was the other way around. Complete choke, when closed completely, and a release for excessive pressure in the case of a backfire. If mine is incorrectly installed, then my logic is...backward.
I will study it more on my return. As we speak, we are trying to get out of Dodge. Didn't get very far before an axle hanger busted on the trailer, and axle tried to fall off. A little come-along, and a tie down strap, and I was able to get it into town. It is now in the shop, and we are in a motel.
Life marches on.
Thanks,
Gary
The flapper may have been backward on my choke assembly. I assumed it was the other way around. Complete choke, when closed completely, and a release for excessive pressure in the case of a backfire. If mine is incorrectly installed, then my logic is...backward.
I will study it more on my return. As we speak, we are trying to get out of Dodge. Didn't get very far before an axle hanger busted on the trailer, and axle tried to fall off. A little come-along, and a tie down strap, and I was able to get it into town. It is now in the shop, and we are in a motel.
Life marches on.
Thanks,
Gary
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