[AT] OT Generator question

[Howard Fleming]

I have a Winco 12KTOC-3/A PTO generator that I run with my Ford 8N that 
originally came off of the family farm (I remember when my grandfather 
bought it new back in the early 60's).

Looking at the armature, there is a section that the copper wire is 
turning green, and a "hole" in it (please see 
http://www.moosebird.net/generator/damaged_section.JPG for more detail).

The generator is currently working well.

Anything that I can do to stop it from getting worse, or is it something 
that I do not need to worry about?

Thanks,
Howard