Alternator problem

[cowsrus]

Does anyone know how to ck an alternator to see if its working. I have an IH 886 tractor and i've changed the alternater out twice now and i still don't have any output voltage. Shouldn't you have voltage at the output lug if you disconnect it and ck with a voltmeter? Mine doesn't and i have 12v at both of the plug-in terminals. I'm stumped! Help. It cks 12v hooked up but doesn't seem to change and i can't tell if its working or not/

 

[DieselPower]

You should never run a alternator with the B+ wire unhooked from it. Is this alternator internally or externally regulated? If it's internally regulated it will not produce any power if the B+ is not hooked up. A alternator can not produce power unless it has power to run off of. The rotor has to have power to produce a magnetic field, no magnetic field, no power produced in the stator assembly.

 

[bobzap]

I usually put a voltmeter across the battery and watch it awhile to see how many volts it is putting out, usually around 14 volts.

 

[Redneck in training]

When engine not running the battery should have about 12V. When engine running it should have about 14 V. In example your headlamps should go brighter.

 

[SPYDERLK]

Are you putting in new alternators or at least ones youare sure work? How many different wire connection points to the alternator? With a functioning alternator the battery voltage will rise above 13V quickly after starting the engine.
larry

 

[cowsrus]

I have 12v at both #1 and #2 terminals. When i ck the voltage i get 12.47 v and when i start the tractor the voltage never rises. i got both alternators at the auto parts stores.
i did figure out that you don't get any voltage when u unhook the main terminal going to the battery, so that helps a little, but i can't figure out why the voltage never goes up even when i turn on the lights and a/c.

 

[Soundguy]

If this is a standard delco 10/12 SI alternator, you need the charge lug hooked to the battery ( thru meter.. etc.. ), the #2 line can be looped to the charge lug. The #1 line can be hooked thru a 194 marker lamp to the switched side of the ignition switch.

If it is a later model.. like a CS130.. it needs 15-45 ohms of resistance in the #1 line.

soundguy

 

[cowsrus]

The #1 terminal line is switched though the switch and the #2 terminal line has 12v present with the sw on or off. i also have 12v at the output lug terminal with the tractor not running. But the voltage doesn't go up any with the tractor running and thats what makes me think its still not working. Most alternators run over 13v and this one doesn't. Do you think the fact that its an alternator originally intended for a chevy truck would account for that?

 

[Matt_Jr]

Do you think the fact that its an alternator originally intended for a chevy truck would account for that?

What do you mean by that?

Anyone have a wiring diagram they can post?

 

[cowsrus]

It's a delco alternator that i bought at the auto parts store instead of buying it from the IH dealer. Shouldn't be any difference unless they were rated at different amps. But i wouldn't think that would be a big problem because a tractor doesn't use any more elec than a car.