For electric motor manufacturers, material choice is becoming a strategic decision. 

Permanent magnet motors have become an important part of electric vehicle powertrains, combining efficiency with high power density. But their reliance on rare-earth materials such as neodymium also exposes manufacturers to cost, availability and geopolitical risks. 

That is pushing engineers to reconsider one of the fundamentals of motor design: whether high-performance electric drives need rare-earth permanent magnets at all. 

One example comes from Japanese automotive technology supplier Astemo, whose rare-earth-free electric motor technology has returned to the industry spotlight. 

A different approach to the EV motor 

Astemo has developed a motor system for battery electric vehicles based on synchronous reluctance technology. 

Instead of relying on the powerful neodymium magnets commonly used in permanent magnet motors, its main drive uses rare-earth-free ferrite magnets combined with a magnet-assisted synchronous reluctance motor architecture. 

The result is a main propulsion motor delivering 180 kW. 

Astemo has also developed a 135 kW auxiliary motor that removes permanent magnets entirely. Designed for use when additional propulsion is required, the unit uses the same multilayer rotor concept but operates as a pure synchronous reluctance motor. 

Read more about Astemo’s rare-earth-free motor 

Replacing rare earths creates new engineering challenges 

Removing neodymium is not simply a case of exchanging one magnetic material for another. 

Ferrite magnets are more readily available, but their magnetic strength is significantly lower than conventional neodymium magnets. That creates an immediate challenge around motor size and performance. 

Astemo’s answer is a specially developed multilayer flux rotor structure. By using the geometry of the rotor to exploit differences in magnetic reluctance, the design compensates for some of the lower magnetic force available from ferrite magnets. 

The 180 kW motor still has an active length around 30% greater than an equivalent neodymium permanent magnet motor, demonstrating the design trade-offs involved. 

Thermal management presents another challenge. 

Generating the required magnetic poles demands higher current through the stator coils, creating additional heat. Astemo has addressed this with an oil-immersion cooling system covering the coil slots and ends. 

These trade-offs matter because they demonstrate the engineering reality behind material substitution. 

Reducing dependence on a critical material can affect motor dimensions, thermal management, winding requirements, manufacturing processes and ultimately system-level performance. 

Material security is becoming part of motor engineering 

The significance extends beyond one motor. 

Motor manufacturers are working in an environment where copper, electrical steel and permanent magnets can all present supply and cost risks. For engineering and procurement teams, selecting materials is therefore increasingly about balancing performance with security of supply, manufacturability and cost. 

Rare-earth-free architectures offer one possible response. 

They are not the only one. Manufacturers are exploring externally excited synchronous motors, synchronous reluctance designs, ferrite magnets and other alternative magnet technologies as they look for different ways to reduce exposure to concentrated rare-earth supply chains. 

Astemo itself is targeting around 2030 for production maturity, meaning its latest architecture should be viewed as an indication of where motor development could move rather than a technology ready for immediate mass-market adoption. 

From motor design to manufacturing 

There is another important question: what happens when these architectures move from engineering programmes into high-volume production? 

A change in motor architecture can affect much more than the rotor. 

Winding systems, insulation, electrical steel, cooling, joining processes, testing equipment and production machinery may all need to respond to new requirements. 

That makes rare-earth reduction a manufacturing challenge as much as a materials challenge. 

For motor OEMs, suppliers and engineering teams, the commercial opportunity will depend on whether alternative architectures can deliver repeatable performance at the required cost and production volume. 

There are already signs of investment in greater electrified powertrain production. Separately, on 1 September Astemo announced an investment of more than $112 million to expand hybrid electric vehicle motor production at two facilities in Kentucky, adding nearly 300,000 square feet of production and warehouse space. 

Read Astemo’s manufacturing investment announcement 

A key discussion for the electric motor industry 

Rare-earth dependency is already firmly on the agenda for the electric motor community. 

At CWIEME Berlin, motor manufacturers, engineers, researchers and suppliers will explore next-generation motor architectures, advanced magnetic materials, permanent magnet strategies, high-performance windings and approaches to reducing material supply risk. 

The question is no longer simply which motor architecture delivers the highest performance. 

Manufacturers increasingly need to ask which designs can combine performance, cost, material security and scalable production. 

Astemo’s work provides one answer. As rare-earth supply becomes a bigger consideration across the value chain, more are likely to follow.