30,000 rpm: How High-Speed Electric Motors Save Space, Weight, and Costs

Dr. Demmerer, at the upcoming Congress DRITEV, you will be presenting a drive concept that operates at 30,000 revolutions per minute. Looking back, we used to operate at 10,000 to 12,000 revolutions, but today 16,000 to 20,000 is standard on the market. So is the further increase in engine speed an evolutionary development?

Dr. Stephan Demmerer: It is indeed the next logical step, but one that represents a real leap forward in technological terms. Speeds have risen steadily over the past ten years, but now we are deliberately pushing the limits of what is still possible with a classic electric motor design. In this way, we want to significantly reduce the size of the electric motor and thus also save on valuable raw materials. If we can achieve a more compact design by increasing the speed, we will gain advantages in terms of cost, weight, installation space, and sustainability.
 

Keyword cost and space advantages: What kind of figures are we talking about here specifically?

Dr. Stephan Demmerer: The savings are significant. We currently expect a reduction in system weight of around 22 kilograms. When you consider that a typical battery-electric drive today weighs around 80 to 100 kilograms, we are talking about an optimization of around a quarter. But just as important is what's inside the machine: the high-speed concept allows us to save around 50 percent of the magnetic material. Since magnets and the rare earths they contain are the most critical and expensive elements in electric motors, that's a significant saving. Our goal is to reduce costs by more than ten percent compared to a conventional electric drive.
 

But when the electric motor spins faster, the transmission has to handle a much higher gear ratio. Wouldn't the modified transmission add more weight and cause higher efficiency losses?

Dr. Stephan Demmerer: That is precisely the trade-off that needs to be resolved. A gearbox with a higher transmission ratio does not necessarily mean more installation space or more weight, because this is where our many years of expertise in gearbox development come into play. Interestingly, and this was also an important finding for us, no loss of efficiency is to be expected. It stands to reason that higher speeds lead to more friction and losses. But in the current prototype status, we have succeeded in using smaller bearings and optimizing the gearing in such a way that the system efficiency remains virtually unchanged – with significantly less material used.
 

Acoustics are often a critical issue at high speeds. An engine that whines at 30,000 rpm would probably be unsellable in a modern, quiet electric vehicle. Is NVH (noise, vibration, harshness) the biggest challenge when increasing the speed of an electric drive?

Dr. Stephan Demmerer: NVH is a very important factor in such speed ranges. The new electric motor concept has a very fast-rotating rotor. This means that the first shaft and the first teeth that mesh with each other have an extremely high engagement frequency. This is the primary source of vibrations and thus noise. To solve this, adjustments to the tooth geometry and the design of the gearbox are necessary. To do this, we use classic design tools and methods, such as rib structures on the housing, but we develop these further to the limits of what is feasible. The proof of feasibility with regard to acoustics in large-scale production is certainly the point that we still need to validate, but it is already looking very good at the prototype stage.
 

You spoke of “evolution instead of revolution.” What does that mean specifically?

Dr. Stephan Demmerer: The target speed of 30,000 revolutions has been set because it allows us to continue pushing the limits of conventional design while still using familiar materials and manufacturing processes. For even higher speed ranges, which are conceivable in the future, further technological advances will be necessary: for example, carbon bandages for the rotor to control centrifugal forces, or a switch from proven roller bearings to plain bearings. This is technically possible but would delay series production and drive up costs.
 

Let's talk about the schedule. How far away is the series launch?

Dr. Stephan Demmerer: Our goal is to achieve industrialization in the 2020s. We are already well beyond the concept stage. The prototype has been running on the test bench since February 2026. So at DRITEV, I will be able to present the latest results directly from the testing. The next step is vehicle integration, which is planned for around the middle of the year. Series production is expected in two to three years, so we are talking about a market launch in 2028 or 2029. This fits in very well with the model cycles of OEMs, who are looking for new solutions for this period.
 

For which vehicle segments is this drive system suitable? Do you see the high-speed motor in the volume market?

Dr. Stephan Demmerer: The advantages in terms of cost, weight, and installation space apply to all segments. The concept is suitable for both primary drives (mostly permanently excited synchronous machines) and secondary drives (mostly asynchronous machines). The portfolio is scalable for any power rating and, among other things, enables another technological leap forward.