GM alt in a flathead question

[Bones]

Pictured is the back of the 12v GM alternator I have to install in a customer's 24 stud motor. What is the smaller post directly below the positive one? If it's a 1wire it should be ground but is this a actually a 2-wire alt? The only reason why I ask is because it looks like there is a wire that will land on that post that connects to the ignition switch? That would follow a 2-wire diagram. Someone had fed the positive to the hot side of the aftermarket fuse panel. Shouldn't that go directly to the battery or is that ok? I appreciate any technical assistance and thank you.

 

[flatheadmurre]

There´s usually markings on the posts that have a function...And it should be isolated from ground so measuring resistance should give you an indication if it´s a ground or other function.

 

[1931flathead]

to me it look like a one wire alternator with the cap over the to

 

[51 MERC-CT]

Can't be of any technical assistance but this is what the back of my GM one wire looks like. Perhaps someone converted it.

 

[Ross F-1]

It's to hold the rectifier bridge in the case. The big tapped lug about 120 deg fgrom the BAT post is usually used for a ground.

 

[Jack E/NJ]

Yes, that seems to be set up as a 1-wire. If there are two spade connectors hidden under the small black cap, it can also be set up as a 2- or 3-wire. 3-wire setups are preferred. http://www.madelectrical.com/electricaltech/delcoremy.shtml

Jack E/NJ

 

[1931flathead]

Can't be of any technical assistance but this is what the back of my GM one wire looks like. Perhaps someone converted it.

you have the black plug two

hook up the hot wire to the big stud and try it see if it charge you might have to bring the rpm up a little to get it to charge

 

[TJ]

The alternator grounds itself through the case to the bracket. The one wire may work or not. It depends on the number of RPMs it takes to "excite" the alternator to charge. I have found it is best to remove the plastic plug and plug on an "exciter" wire so the alternator starts charging as soon as the motor fires up.

 

[Ed Pitts]

Here is my 3 wire on my car. Ed

 

[51 MERC-CT]

you have the black plug two

hook up the hot wire to the big stud and try it see if it charge you might have to bring the rpm up a little to get it to charge

Yes it has the black plug also and it works perfectly as a one wire alternator. There are not any charging problems.

 

[1931flathead]

some times you have to bring the rpm up a little all depends on how it is set up in it the guy have do mine they will charge at a idle