Energy conversion difference in permanent magnet vs. field coil motor

[BruceRH80]

New here, hello all.
My question is more about the field magnet in a running DC motor. First of all, does the current required to maintain a magnetic field change with the load on the motor? And if so, where would this "extra energy" come from in a permanent magnet DC motor?

 

[CWatters]

The field winding has higher resistance then the armature winding (perhaps three orders of magnitude?). I don't believe the field current changes much with motor load.