Hemi 12v Generator posts - which is arm & field?

I have a 12v chrysler generator. It has the tag on it, so if needed, I can get that number.

There are two posts on the generator. One of the posts is slightly thicker than the other. I don't see any labels on the generator.

Which one is Field and Arm?
Do I need to run a ground from the generator?

 

Armature post is the big one, field the smaller one. Hope this helps. A ground from the generator to the base of the regulator is a good idea.

 

e1956 is correct and definatly ground it. been there done that

 

Thanks for the info.