No Magnets, Big Power: BMW’s Fifth-Generation Electric Motor


No Magnets, Big Power: BMW’s Fifth-Generation Electric Motor

We’ve hinted at the impressive power output of the BMW iX M60 motor in our First Look, but its fifth-generation electric motor technology deserves its own examination. That’s because it’s both extremely high-tech and a little bit old-school. Here’s what you need to know, and why it’s so interesting that BMW used this motor on the iX M60. It’s a big advance in terms of the efficiency of the electric motor, while getting away from the use of rare earth minerals.

Before we dive in any further, if you’re not familiar with the different types of EV motors used in vehicles, we have a thorough E-Motor 101 course. Feel free to open that in another tab and use it as a reference. But all electric motors rely on the properties of electromagnetism to convert electricity into torque to drive the vehicle. One pole of a magnet being attracted to the opposite pole of another, and like poles repelling each other, is what drives an electric motor. An easy approach is to use strong permanent magnets in the spinning part of the motor called the rotor, and an electromagnet (conductive wires wound around a ferromagnetic material) in the stationary “can” it spins in, which is called the stator. Reversing the electric polarity in the electromagnet reverses the magnetic polarity, and it’s this switching that pulls the permanent magnets around. But the rare-earth materials that make permanent magnets are getting hard to find, so BMW is getting away from them by using electromagnets in both the stationary stator and the spinning rotor. It’s relying on an old technology—brushed motors—to make this possible.

For the full story, check out this article from Motor Trend.