Tim Woolmer, founder and CTO, thinks his axial-flow motors could be a mobility game-changer
back in julyYASA (formerly Yokeless & Segmented Armature), a British electric motor startup with a revolutionary ‘axial-flux’ motor, was acquired by Mercedes-Benz. The acquisition didn’t really attract heavy press attention, as other details were announced. But YASA has the potential to be an entity worth watching.
Founded in 2009 after splitting from Oxford University, YASA will now develop ultra-high-performance electric motors for Mercedes-Benz’s AMG.EA electric-only platform. It will remain in the UK as a wholly owned subsidiary, serving both existing customers such as Mercedes-Benz and Ferrari. The company will maintain its own brand, team, facilities and location in Oxford.
YASA’s axial-flux electric motors generated interest in the EV industry due to their efficiency, high power density, small size and low weight.
In contrast, the ‘radial’ electric motor design is more common in today’s EV market. Even Tesla relies on radial electric motors, a legacy technology more than 40 years old with little left to deliver in terms of innovation.
But YASA’s axial-flow design, which has very thin sections, means they can be combined into powerful single drive units. This makes them one-third the weight of other electric motors, more efficient, and with 3x higher power density than Teslas.
Tim Woolmer, YASA’s founder and CTO, invented this new approach to electric motor design. I contacted him to find out what’s next.
TCWhat is the journey so far?
two: We started 12 years ago with a really send-off: Let’s make electric cars faster, do anything we can to make electric cars faster. We are now 10 years into a 20 year revolution, every new car sold in 10 years will be electric, no question. Nothing is more exciting to an engineer than a period of revolution because the pace of innovation is important. The most exciting thing for us is that we get to innovate fast, and that’s where the partnership with Mercedes gets really interesting.
TC: What was the difference with the engine you came up with?
two: We started with a blank paper at the beginning of our PhD. And the idea was to say, what could be built for the electric car industry 10 or 15 years from now, that they would need, that we could meet. Something that was lighter, more efficient, mass-producable in quantity. In the 2000s, axial flow motors weren’t very common, but by combining axial flow technology and using some new materials to make some small changes, I basically stumbled across this new design we call YASA: Yokeless and Segmented Armature Huh. This takes a light topology in the axial flux and makes it even lighter, about half that again. There is an advantage because the rotors are rotating to a larger diameter. So, essentially torque is force times diameter, so for the same force, you get more torque. So if you double your diameter, you get double the torque for the same amount of material. So this is the advantage of axial flow.
TC: You’ve made a deal with Mercedes – what’s next?
two: We are basically a wholly owned subsidiary. We’re going to use Mercedes’ industrialization powerhouse. But the important thing is, if you look at how technologies filter in automotive, they start in the luxury sector, like the Ferraris of this world, and then filter into the mainstream sector and then in high volumes. Goes. This is a place where Mercedes is world-class in terms of their industrialization, so that’s kind of the idea behind the partnership.
TC: What else can you do from here?
two: We will have a very high, high power, low density and lightweight engine so that we can find sporting performance with a high degree of industrialization. It puts us in a really unique position for all kinds of things.
Though worried about his future plans, Woolmer is definitely one to watch in the EV and electric motor space. YASA released this video after the acquisition: