Electrical Steel: The heart of an electric motor

Stronger magnetic flux, higher efficiency

Are powerful batteries the most important thing for electric motors in cars? Not quite; a very special material is needed to get the power from the battery onto the road: electrical steel. Electrical steel is a soft magnetic material. In such materials an external magnetic field generates a magnetic flux density that is many times higher than would be the case in air. In simple terms, the magnetic field is strengthened by the soft magnetic materials. Flux density is key to the torque of an electric motor.

Electrical steel is a soft magnetic material. In such materials an external magnetic field generates a magnetic flux density that is many times higher than would be the case in air. In simple terms, the magnetic field is strengthened by the soft magnetic materials. Flux density is key to the torque of an electric motor.

Core losses are another important criterion for the efficiency of electric drives. These losses occur due to the constantly changing direction of the magnetic field; as a result, part of the energy used to power the electric motor is lost as heat. The level of core losses depends on the frequency with which the direction of the magnetic field changes – and of course on the quality of the electrical steel.

A very special material is needed to get the power from the battery onto the road: electrical steel.

For conventional electric motors, such as those used in elevators or machine tools, the frequency is 50 hertz. By contrast, high-speed motors for electric and hybrid cars have frequencies of more than 400 hertz. So the goals for electrical steel developers are clear: Electric cars need soft magnetic materials with high flux density and minimal core losses at high frequencies. We have developed electrical steel with 30 percent lower core losses than current standard grades.