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.

 

[DieselPower]

Try only posting a question once. Duplicate threads make it difficult to follow.