How do I check whether my tractor alternator is working

[tommyboy1]

I was able to try a couple of suggestions that you gave me yesterday to test the alternator on my tractor and here are the results:

1) checked battery before starting tractor: 12.3 volts after running tractor a couple of minutes 12.3 volts.

2) ran the tractor at different rpms and still 12.3 volts

3) cheched the voltage at the alternator (still had the battery connected so I don,t know if this reading means anything) 12.3 volts, Although at times,it seemed as if the voltage was fluctuating all over the place. I had no clips from the voltmeter, just hand held, so I'm not sure if I had a good contact at all times. I felt that I held the meter probes fairly consistent.

4) turned on the lights after the tractor was running - no noticable change in sound with engine. As if no load was applied.

5) no ammeter to check if needle would move

6) checked voltage between positive post on battery to negative post on starter and neg post on battery to pos post on starter and got 12.3volts both checks. not sure if I did this right because I should have come up with 0 volts to.5volts according to diesel lover.

I'm not sure what these measurments mean to any of you, but it seems as if the alternator is not working to me. any comments or suggestions would be welcome.

 

[TomSeller]

Sounds like the alternator, you did not detect a ~14V charge voltage. I believe DL had you checking the cables in your step 6, staying on the positive or negative side to where the voltage should have been 0. It looks like you positioned your leads to opposite side.

 

[Coyote machine]

Never disconnect either cable from the battery when the engine is running. That is a surefire way to damage the alternator diodes.
With the engine off connect the VOM meter leads to the battery posts, start the tractor and see what the meter reads both before and after starting. With the engine running put on the high beams and see what the meter reads. You should go from around 12V with engine off to 13V or so with running, to 14.25V with load, (lights on).
Anything less than 14V with high beams on, and the alternator is not putting out enough amps to keep battery charged, or you have a bad external V. regulator, or a bad or broken wire in the charging circuit.

 

[Coyote machine]

I was able to try a couple of suggestions that you gave me yesterday to test the alternator on my tractor and here are the results:

1) checked battery before starting tractor: 12.3 volts after running tractor a couple of minutes 12.3 volts.

2) ran the tractor at different rpms and still 12.3 volts

3) cheched the voltage at the alternator (still had the battery connected so I don,t know if this reading means anything) 12.3 volts, Although at times,it seemed as if the voltage was fluctuating all over the place. I had no clips from the voltmeter, just hand held, so I'm not sure if I had a good contact at all times. I felt that I held the meter probes fairly consistent.

4) turned on the lights after the tractor was running - no noticable change in sound with engine. As if no load was applied.

5) no ammeter to check if needle would move

6) checked voltage between positive post on battery to negative post on starter and neg post on battery to pos post on starter and got 12.3volts both checks. not sure if I did this right because I should have come up with 0 volts to.5volts according to diesel lover.

I'm not sure what these measurments mean to any of you, but it seems as if the alternator is not working to me. any comments or suggestions would be welcome.

I didn't see this post before I posted above. Your charging system is NOT charging the battery. What is causing the problem is now up to you to determine, read above comments. Before you replace anything make sure you don't have a loose, frayed, burnt, broken connection between the wiring from the alternator to the Voltage regulator, IF it's external, or to the battery, amp meter, if one is present. You need the 14+Volts returning to the battery with the load,(lights on) to properly charge the battery, or it will continue to die until it's completely dead and won't take a charge.

 

[tommyboy1]

thanks for the input guys. I will check all the connections between the alternator and battery before I do anything else. I will also make sure all connections are clean for good contact.

 

[Dave M7040]

thanks for the input guys. I will check all the connections between the alternator and battery before I do anything else. I will also make sure all connections are clean for good contact.

Can you post a picture of the alternator and the area around it so we can see if there is an external voltage regulator. Perhaps you already know this but I don't recall you saying. If the regulator is inside the alternator, I would be looking for an independent starter, generator repair place and ask them to check your alternator. You don't need your dealer in the middle of this. This way you can provide the repair guy with first hand accounts of what you have done and experienced and the outcome will be much better.

You can easily damage an alternator! When you buy a rebuilt one often there is literature enclosed with it cautioning you to charge your battery before installing the rebuilt alternator to avoid over working the alternator dealing with a nearly dead battery. Take the negative battery cable off before removing any wires from the alternator.

Good luck and keep us posted.

Dave M7040

 

[diesel lover]

thanks for the input guys. I will check all the connections between the alternator and battery before I do anything else. I will also make sure all connections are clean for good contact.

Check your belt and tention asap!! Good thing to check. Remember to coat connections with spray paint. Any corrosion can cause no or little electrical flow.

Is this a tractor you are currently using to plow snow and you rely on it for that?

 

[tommyboy1]

YES, I snow blew with it last night. directly after, I put on the battery charger and it had already lost some charge without the use of lights. howevwer, the blower does have an electric powered chute rotator.

I will check the belt tension tonight. I checked it last summer and it was fine but I will check it again. You never know, it could be something that simple.

 

[tommyboy1]

if I have time, I will take a picture and post. I don't really know if the tractor has an internal voltage regulator.

But looking on-line, I think that it may be external. where are they normally located? near the alternator, by the instrument cluster?

 

[Industrial Toys]

My thinking would be on the firewall. Sorry, I never knew their was a risk of blowing the diodes in your alternator by removing the battery while running. You say you don't have a dash mounted ammeter, but you must have an idiot light, no? Is it on? Does it come on when you turn on the key, but before you start the engine?