That's really interesting that they picked brushes; Renault's EESM motors are similar but use wireless power transfer to excite the rotor windings. Maybe brushes can pass more current cheaply?
Yes, brushless necessitates more rotating mass plus the loss in the wireless exciter. Longer life (no brush changes or slip ring wear), but lower efficiency.
I wonder if a hybrid rotor would pay off? It would still need brushes, but the current could be less to make them last longer. Probably a problem with demagnetizing the fixed magnets or something.
I wonder if a hybrid rotor would pay off? It would still need brushes, but the current could be less to make them last longer. Probably a problem with demagnetizing the fixed magnets or something.