How do I check generator?

[Anonymous-0]

The generator on my TO20 doesn't seem to be put out any current! How do I test for out put? I can't seem to get any reading on the 2 termals on top gen. any way I check it! Thanks for coments, this forum is great; used many of yall suggestion! Thanks again Gene

 

[greenbank]

The easiest way to check for charge is to simply run a volt tester between the positive and negative terminals when the engine is running. You want to see 7 volts or so on a six volt system, 13 or so on a 12 volt system. If you don't have that you don't have charge.

 

[greenbank]

Sorry, positive and negative terminals OF THE BATTERY.

 

[Jeff-oh]

I think what Greenbank is implying... is
measure the Voltage of the battery before you start the tractor. Write that down.

Now start the tractor and measure again. If charging the voltage will go up if the system is working.

To measure the generator directly put your leads on the Field Pole and the other to a ground.

It can be hard to get a good connection particularly through paint. Has you generator been polorized?

 

[gshadel]

this kind-of builds on the other guys replies. Your generator & voltage regulator are wired together, the regulator controls the gen. output. If the regulator is acting-up, your generator output will be zero. If you check the volts across the battery with engine running & engine off, and conclude your generator is not charging. You still need to decide if you have a generator problem, or a regulator problem. The easiest way to do that is to run your engine at working speed (not idle), take a piece of wire and connect the (F)field terminal on the generator, to a good ground, like the ground lug on the back of the dash, or the pos. terminal on the battery. Make sure your ground lug in clean & shiny. When you jumper the generator like that, it FORCES your generator to it's full output, which is ~7.2V or so. You should see that voltage across your battery. If you don't see the voltage increase when you jumper the generator to ground, you either have a bad wiring connection from the generator armature (A) terminal, or the generator is bad. If that test does give you the desired volts, then take a look at your regulator. A common cause for regulator problems is a corroded ground on the regulator. One of the mounting bolts acts as the gound, if corroded... no charging.
All this assumes a few basic assumtions with your stock 6V TO-20 system - positive ground, 6V battery, clean & shiny terminal connections (6V is very suseptible to corrosion), and that your generator has been polarized. All those things need to be in place first before tearing into the generator & regulator. The generator is typically very easy, and inexpensive to fix if you find it is not charging.


George

 

[Anonymous-0]

Hello.......Anybody else get an errattic voltage reading across the battery terminals with a digital volt meter,,,,,,,do I need a needle type voltmeter to get a proper reading when the tractor is running? Thanks Ian

 

[Anonymous-0]

I don't use the tractor that much; so not sure if polorized; so please explain! When I remove the jumper cables she dies, battery very weak, could this be the problem??? thanks Gene

 

[Fergie fan]

I have a TEA 20 85 that has been running negative ground for years, tractor runs great with no problems. Should I be switching it back to positive ground or has somebody in past possibly rewired the coil for negative ground. Motor was rebuilt about 20 years ago by local mechanic.

 

[Mark from the Fort]

Had the same experience when I was trouble shooting my 6 volt system---digital reading were all over the place.
I bought a $9.00 (needle type) and worked fine....I think there is aLOT of electrical interference on the tractors.
I actually like the needle tester better for everything now.

 

[John H TO20]

I took my generator and voltage regulator to and automotive electronics shop and had them test it. You may be able to see if it's charging by measuring voltage across the battery terminals. But, your ammeter should do that too. I knew mine wasn't charging but didn't know enough to figure out what was wrong. According to the guy at the shop there are a lot of imported 6V regulators that simply don't work correctly. He replaced mine with one from a manufacturer that he knew to make good 6V regulators and rebuilt the generator. The regulator and rebuild cost $130 but now it charges fine. I'd recommend you find a local shop that repairs automotive electronics and take your generator & regulator it to them,

 

[gshadel]

If your TEA runs happily with negative ground, than leave it. The Pos. ground is more for the ignition efficiency than the charging. The generator will work either way. It just has to be polarized prior to start-up so the ouput is the correct polarity. An alternator has to be negative ground, so all 12V systems are negative ground.

George

 

[Jeff-oh]

I would suspect the weak battery is to blame. I had the same problem with a Chevy Blazer last summer. Problem is we were 30 KM North of Dubreuilville, ON. Thank goodness for the ACR tracks and good maps.

 

[Jeff-oh]

Sorry I forgot to answer your question. Yes a weak batter can kill the motor. Recharge the batter and see how it works.

On my MF-65 I was driving it home at dusk after working. The generator was not charging properly and when I turned the light on it would run irratic. Take that electrical load off and it smoothed out.

Thus, I ran at late dusk, on a slow tractor with no lights. Though when a car was comming in either direction I would turn them on for safety.

For polorizing the generator you momentaritly attach a jumper cable from the ground terminal on the battery to the Field pole on the generator. Per the manual this is done with the engine NOT running. I just read thin in the service menual on Sunday, and think I have the right terminal, but I will double check tonight.

Jeff

 

[Anonymous-0]

Thanks for all the replies: Yes; Jeff I think you are correct; she wont run with a DEAD battery, I got a little charge in it & jumped it off & she run fine back to her parking spot, 30yrds. I hope that was all and not the regulator. Thanks to all. Gene

 

[Covert]

If you have a generator after you start your tractor you can un-hook the battery and it should still run. Current is measured through inductance. If you want to see how many amps your generator is putting out you need an amp probe, or multi-meter with amp reading. You can not get and amp reading by going across the terminals. Amp readings should be done from around the load side wire.

 

[David, Surrey UK]

(quoted from post at 16:51:04 10/02/07) Hello.......Anybody else get an errattic voltage reading across the battery terminals with a digital volt meter,,,,,,,do I need a needle type voltmeter to get a proper reading when the tractor is running? Thanks Ian

The output from a generator can be quite jittery as the field winding is switched in and out by the regulator, and that can cause problems particularly with cheaper digital meters that are susceptible to noise. This will be worse if the battery has a high internal resistance, i.e. it's on its last legs. Anyway, measure the voltage right on the battery lugs to minimise the effect.

If I had this problem I'd make myself a little lowpass filter with a resistor and capacitor to smooth the voltage feeding the meter. 1 kilohm and 1000uF should do the trick. :wink:

David