Flux-vector drives from Yaskawa Electric America Inc., Waukegan, Ill., go in highly accurate, self-cooling gear dynamometers used to test differentials for NASCAR Nextel Cup cars. The dynamometer maker, G-Force Transmissions, Cleona, Pa., chose electric motors and the Yaskawa drives over conventional "tractor" dynamometer designs that rely on throttled hydraulic motors and pumps for power and load. Such tractor dynos lack control sensitivity needed for the work. Read more