We all know electric motors are torqueful, but there’s a price to be paid for all that torque. Since electric cars use motors that have rare earth metals inside, they’re also expensive. A team of researchers at the Tokyo University of Science has discovered how electric motors can be made from cheaper and more convenient materials.
The team even built an electric car featuring the motor they invented, and showcased it at Techno-Frontier 2011.
“Tokyo University of Science is developing an electric car that is the same size as a second generation Prius and is powered by a so-called switched reluctance motor that uses absolutely no rare earth metals and has an output of 50kW with 95%-plus efficiency,” says associate Professor Nobujazu Hoshi, in whose lab the researchers built (or, better said, modified) the car.
The switched-reluctance motor they built uses the difference in magnetic resistance for producing mechanical work. It is both heat resistant and can easily survive the mechanical shocks that a car challenges it to.
The downside is that it doesn’t have as much torque as its siblings that use rare earth metals and permanent magnets, but it is nevertheless cheaper, which is sometimes better for people who don’t need that much oomph in their normal cars, after all.
Further tests have to be conducted for the motor to be integrated in serial production, as Hoshi says: “There is a concern that noise and vibration might be problems when the motor is loaded into a vehicle. So, I will experiment with control methods and new structures to reduce noise and vibration by conducting trial tests, as well as design and develop a motor drive circuit.”