12 volt alternator

A good 12v battery will have a charged voltage between 12.4 and 12.6 volts. If the tractor is running, the voltage at the battery (charged battery) should be between 14.2 and 14.7 volts. If the battery goes dead when it is shut off, checking the alternator includes removing the wire from the big post and tapeing it up so it can't short to anything. If the battery still goes dead, also disconnect the wire from the ignition to the Alt or regulator. If it discharges then it is not the alternator, as it is isolated. If it is a "one wire alternator" it has a good chance of being at fault. They are not standard Delco, they have a different regulator inside that is always on to some degree. This drain is big in some of them, and quite small in other one wires. I recomment=d a 3 wire "normal" Delco 10SI to eliminate this drain. Jim
 
I hold a screw driver to the back of Alt.brg as the tractor is running at high rpm and if screw driver magnitizes I know that it is chargeing. Just my way.
 
That's the way I've always quick checked them. If it pulls a small screwdriver, hacksaw blade, or whatever against the bearing, it's charging.
 
I want to thank everyone of you guys that gave me the information on how checking Alternator Each and everyone of those worked. Bad regulator and diodes in Alternator. Thank you
 

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