ALT FIELD CB vs ALT CB
 

Hello folks

for the geeks outhere i was just wondering what is the practical difference between the ALT FIELD CB controlling the the field current to the field coils of the alternator and controlled by the VR and the ALT CB between the ACU and the bus network?
In case of an overvoltage shouldn t both CB's pop?
Maybe the diagram is misleading, maybe what is shown as an ALT FIELD CB is not a real CB but just a relay operated by the VR?
What would cause the ALT FIELD CB to pop without the ALT CB popping?

Many Thanks

Baobab