Oshkosh is using motors
with die-cast copper rotors
in its ProPulse series hybrid
drive system, which is used in the Army's heavy cargo-hauling HEMTT (Heavy Expandable Mobility Technical Truck). Motors using this technology cost less to manufacture, last longer, operate more efficiently, and save weight compared to alternatives used in defence systems as they're between five to ten percent lighter and three to seven percent smaller. The rotors were developed by the Copper Development Association (CDA) as part of their Copper-Based Casting Technology (C-BCT) program.
Substituting copper for aluminium in the rotor conductor bars will generally increase motor efficiency due to copper's better electrical conductivity, but redesigning the motor around copper's strengths provides an opportunity to achieve even greater improvements. The result: an induction motor with the highest power density possible today.
Four 140hp / 104kW electric motors power the HEMTT-A3 severe-duty trucks, which utilises a 400hp / 298kW diesel
engine to provide electricity to the 480V motors.
[Source: Green Car Congress]