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.


Related:

• U.S. Army considering hybrid trucks
• Garbage trucks get hybrid power

[Source: Green Car Congress]

In all the progress and developments we've seen on with hybrids, electric cars and fuel cells, it's a bit strange how little we've reported on the advancement of electric motors. That's something that Raser is definitely looking to change. At the 22nd Electric Vehicle Symposium (October 22 to 28) in Yokohama, Japan, the electric motor specialists will unveil a new 100 kW AC induction-based electric motor design called the Symetron P-100.

Raser's AC induction-based technology was recently awarded the Drive System Technology Innovation of the Year Award by Frost & Sullivan, so you can imagine they're pretty proud of it. Its key feature is the absence of expensive permanent magnets which the company hopes will bring the cost of next-generation of hybrids and electric vehicles down within the reach of more customers.

In terms of performance, consider the electric power plant at the core of the world's most popular hybrid, the Prius, as a point of reference. At 50 kW it delivers 67 horses and 297 lb-ft of torque. The 2006 Civic Hybrid? While still very economical, it only offers a 15 kW motor which is good for 20 hp and 76 lb-ft. Raser's press release, doesn't actually state horsepower or torque figures, but you get the idea. If all goes well, it seems like the next generation of electric-powered vehicles are going to be a thrill to drive.

[Source: Raser]