YASA reported today that it has smashed its own unofficial electric-motor power-density world record.

Earlier in the summer, the global leader in the design and production of axial-flux motors achieved 550 kW from a 13.1-kg version of a prototype motor, equating to what it says is an unofficial power density world record of 42 kW/kg. The latest testing of an even lighter 12.7-kg version has significantly exceeded this. Hitting a 750-kW short-term peak rating, the company has just set a new unofficial electric motor power density world record of 59 kW/kg—a 40% increase on initial testing.

“This record demonstrates what makes YASA unique,” said Joerg Miska, YASA’s CEO. “With three times the performance density of today’s leading radial-flux motors, YASA continues to redefine the boundaries of what’s possible in electric motor design—turning pure innovation into tangible engineering progress. Our technology is delivering measurable results today, while paving the way for a new generation of lightweight, efficient electric propulsion systems.”

A wholly owned subsidiary of the Mercedes-Benz Group since 2021, YASA is aiming to redefine electric vehicle performance. The company employs over 400 people across sites in Oxford, Bicester, and Welshpool in the UK. It says its revolutionary axial-flux electric powertrain technology brings the highest power/torque densities in class for the smallest size and weight.

Designed and developed at YASA’s Oxford Innovation Centre, the company believes the latest breakthrough represents another major validation of its axial-flux technology. Crucially, it isn’t a theoretical model or digital concept; it is a fully functional prototype, undergoing a rigorous development program. The motor was designed and developed with support from the Advanced Propulsion Centre UK.

“To achieve a 750-kW short-term peak rating and a density of 59 kW/kg is a major validation of our next-generation axial-flux technology,” said Tim Woolmer, YASA’s Founder and CTO. “It’s proof of what focused engineering innovation can achieve. We’ve built an electric motor that’s significantly more power-dense than anything before it—all with scalable materials and processes. This motor will bring game-changing technology to the high-performance automotive sector.”

Compact, scalable, and without exotic materials, the motor achieves exceptional performance through precision engineering, advanced thermal management, and optimized packaging. The impressive compactness of the motor is demonstrated by YASA R&D Engineer Eddie Martin, who holds the new 12.7-kg prototype in one of this article’s images.

YASA’s engineering team is already validating the prototype through extended testing cycles. The company says that the motor is not just focused on setting new standards for peak power, estimating that its all-important continuous power will be in the region of 350-400 kW.

“The early results are extremely encouraging,” said Simon Odling, YASA’s Chief of New Technology. “The motor’s performance on the dyno has exceeded even our most optimistic simulations. As well as its incredible peak power and overall power density, we estimate this new motor will be able to deliver all-important continuous power in the region of 350-400 kW. This is real hardware, in real life, delivering real data—and it’s performing beautifully.”

Futurride last covered YASA’s technology in July as a contributor to Mercedes-AMG’s Concept AMG GT XX, which delivers its power through an all-wheel-drive powertrain featuring three axial-flux electric motors to reach speeds of more than 223 mph (359 km/h) thanks to a peak output of over 1000 kW. For application in the concept and then series production vehicle, the YASA tech was integrated by Mercedes-AMG experts who developed the operating strategy software that enables high output from a compact package. It will enter series production at Mercedes-AMG in 2026.

Compared with conventional radial-flux electric motors, Mercedes says that axial-flux motors are one-third the size, two-thirds lighter, and have triple the power density. The compact motor’s design offers more flexibility when it comes to drivetrain packaging.

In the concept vehicle, the three motors are packaged into front and rear HP.EDUs (high-performance electric drive units). The rear has two axial-flux motors, each equipped with a compact planetary gearset and one inverter in a single casing that is around 3.1 in (79 mm) wide.

In an axial-flux motor, the electromagnetic flux runs parallel to the motor’s axis of rotation rather than perpendicular as in a conventional electric motor. The stator is positioned between two rotors, the layout enabling optimum power transmission to the rotors through the electric field generated by the stator.