Field vs. Armature

[Joe Flanagan]

As you might have read in a separate thread, I'm currently trying to figure out a problem I have with my generator overcharging. I've been going over everything and I have a question about the terminals on the generator. As I understand it, the larger post is the armature and the smaller one the field. But I had this generator rebuilt at a shop and it looks like they replaced the old studs with new ones that are of identical width. One is longer than the other, but both take the same size nut. I assumed the longer one was for the armature terminal but the more I think of it, I'm not so sure. Is there any way to tell aside from taking the generator out of the car and disassembling it? 

[desoto1939]

Joe:  I would call the shop that did the repair and ask them why they chnage the size of the posts and also to get them to tell you which post is field.  They should beable to tell you.

 

Rich HArtung

[Plymouthy Adams]

Joe could it be that the very post they used is actually shorting the field to the case which is ground and thus the resulting overcharge be the results....look carefully at the insulator on that post...read it to case with the ohm meter..

[Joe Flanagan]

Tim, I've checked both posts (with the case separated from the armature) and I find no contact between them and the case itself. It seems they're properly insulated.  

[Don Coatney]

If you have the generator opened up trace the wires from the brushes to a stud and that will be the armature. Then trace the wire from the field coil to the other stud. That should provide your answer.

 

[Joe Flanagan]

Thanks, Don. Just out of curiosity, does anyone know what would happen if you got the wires reversed? 

[Joe Flanagan]

I took the band off the generator and I was able to see through the open space to where the wires go. Thanks, Don, for that tip. I did have the generator wired correctly.

[P15-D24]

A lot of times they will have an "A" or "F" stamped in the case near the terminal.