Need rare earth metals? Switched-reluctance motors don’t

Most hybrid and electric vehicles rely on rare earth metals. There’d be nothing wrong with that if China didn’t supply in excess of 90 percent of the world’s rare earth metals. Why is this a problem? Because China’s recent decision to slash export quotas on rare earth metals has caused a surge in prices, for one thing.

Building a vehicle like the Toyota Prius requires 20 to 25 pounds of rare earth metals, including two-plus pounds of neodymium. Since China’s government is trying to curb exports of rare earths, interest in electric motors that don’t rely on rare earth metals has boomed.

One technology – developed by St. Louis, MO-based Nidec Motor – called switched-reluctance motors (SRMs), might offer a viable alternative. SRMs use a variable-speed steel rotor that spins within a housing that contains bundles of wires. Scott Nieberle, vice president of Nidec Motor, says that, “Essentially, you can get the same type of performance without needing to use rare-earth magnets.”

The commercial viability of SRMs has increased over the past three decades. In early 2011, John Deere launched two diesel-electric hybrid construction loaders equipped with SRMs. Though SRMs haven’t been specifically designed for use in automobiles, Nidec says that it wouldn’t take much to make SRMs that compete with rare earth metal-dependent motors used in most of today’s electrified vehicles.

[Source: New York Times]