Tiny electric motor can produce more than 1,000 horsepower
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A new electric motor developed by YASA, a Mercedes-Benz subsidiary, can produce over 1,000 horsepower while weighing only 28 pounds, sparking discussion on its potential applications and implications for the automotive industry.
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At this point why don't we get rid of the k prefix and write 59W/g?
Edit:
I was half joking, but various answers mention kW being standard for motors, kg being the SI unit for mass etc. All true, but as used here in a combined unit, which means "power density" it still would make sense IMO. It's not like the "59" tells you that it's a strong motor and hence you want kW to compare it to other motors. You can't, it's just a ratio (power to weigth). W/g just reads much nicer in my head. Or we could come up with a name, like for other units. Let's call it "fainpul" (short fp) for example :)
59 fp is a new record for electric motors!
Same reason you wouldn't use m²/s³ even though that's also technically correct.
Kilo is an SI prefix.
"The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.62607015×10−34 when expressed in the unit J s, which is equal to kg m2 s−1, where the metre and the second are defined in terms of c and ∆νCs.[1]"
The base SI unit for power is the watt. The base SI unit for mass is the kilogram. Yes, this is dumb, but it's the way it is.
[1] https://www.bipm.org/utils/common/pdf/si-brochure/SI-Brochur...
Could the motor in question be shrunk down to 1kg, producing 59kW? Probably.
Could it be shrunk down to 1g? No.
No, it tells you nothing about the absolute size of the motor, but for the rest of us, the context clues are there to gain additional information. Someone else constructing something that obfuscates this with a micro-motor doesn't make this useless.
Significant figures exist for a reason. You are ignoring that here and creating precision that does not exist. The kilo-prefix absolutely communicates scale information to most readers.
Similarly it is useful to talk about household electricity consumption in terms of kWh/day, despite that also being a ratio that can reduce down.
The goal here is communication, not theoretical mathematical optimality that is actually worse in every real way.
It makes it easy to compare ratios: for example the aspect ratio of a movie (say 2.39) to my screen (2.33) and see that I can expect a good fit. My screen is a bit "more square", so there will be slivers of black borders on top and bottom.
Instead of 24" screen with a 16:9 ratio they should just be sold as 53 x 30cm.
Look at the silliness with folding displays where the difference in diagonal seems marginal until you open up a folding phone and realize that diagonals are just a silly way to measure things.
The YASA link is primary, links to test data and back story, and has more detail substance and authority.
YASA was founded in 2009, a spin out from Oxford University following the PhD of founder and still CTO, Dr Tim Woolmer.
"Over the decades that followed both of these technologies were explored. But despite the potential for weight reduction, smaller size, shorter axle length and increased torque, it was the difficulty in manufacturing the axial flux technology that limited its commercial viability, because the motor could not be made by stacking laminations, as with radial machines."
"The breakthrough innovation came by segmenting the axial flux motor in discrete "pole-pieces", so the motor could be manufactured using Soft Magnetic Composite material.
SMC can be pressed at low cost into a wide variety of 3D shapes. This removed the need for the complex laminations, overcoming the major manufacturing challenge of the axial flux machine."
"In 2025, after a £12m investment, YASA opened the UK's first axial-flux super factory, in Oxfordshire.
The opening of this facility boosts YASA’s manufacturing capacity, setting new benchmarks in e-motor technology and quality, and enabling production to scale beyond 25,000 units per year."
This is awesome. Lighter motors also make electric flight more viable
In an ICE, the same load is less visible because most energy gets wasted as heat. This is also why cold weather seems to affect EV range more.
There's a kernel of truth here in that Otto engines suffer lower efficiency at part load, however I suspect the real reason is that gas car range is "good enough" and refilling is fast, so one doesn't tend to obsess about remaining range.
> This is also why cold weather seems to affect EV range more.
That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
You are making my point here actually. Combustion engines suffer from the exact same, but because they waste so much energy as heat already, less “extra” energy needs to be spent on that.
Yes heating impacts range in an EV, but it's not really an efficiency thing, it's because you can't get it "free". If an ICE didn't let you harness the heat, you'd see a similar percent drop in range.
And for extra weight, it's just not true. Making a motor work 10% harder at 90% efficiency, compared to making an engine work 10% harder at 20% efficiency, both of these are going to reduce your range by 9%.
> No wonder electrics don't sell well in the US. People weigh more, you're basically saying that leaving grandma at home, is a "game changer".
Even in the US, your average grandma weighs less than 2-300kg :D
250kg weapons = ~20 small dogs
Instead of technological advancements of EV motors, we can immediately use existing pharmaceutical tech (Ozempic, GLP-1) to immediately deliver weight reduction to cars. However, this will be immediately offset by the increase in weight of weapons carried, thanks to Jevons Paradox.
If we could indeed leave "grandma" home, that would make things better.
And they don't sell well in the US because of oil lobbying and think tanks whose sole goal is to make you buy more oil.
https://electrek.co/2023/04/27/saab-engineers-develop-secret...
There are probably a range of application where in-wheel makes perfect sense.
Do e-bikes really need significantly more power than they have? They already run arguably dangerously fast for their application. Is efficiency not the primary target there?
The lower weight would be definitely welcome, my ebike is comically heavy compared to a normal one and sometimes I have to carry it up flights of stairs (some German railway overpasses, grr).
Also in scooters it could fit in the wheel (since the wheel is tiny and has to spin quite quickly - no reduction gear needed vs a bike with 26-28" rims) allowing a simpler design and cost savings. But maybe in scooters they're already using in-wheel motors, I'm a bit ignorant there.
Oddly, a very large majority of current fully suspended e-bikes with rear cargo racks have those racks unsprung, which suggests that most e-bike manufacturers don’t actually care about the handling of anything other than their pure e-MTBs.
Ref: https://www.cyclinganalytics.com/blog/2018/06/how-does-your-...
I'm always interested to hear about the latest in lighter and possibly more powerful and torque-y e-bike motors.
From https://lammotor.com/yasa-axial-flux-motor/
the shape is due to the change to the motor layout: https://www.thedrive.com/news/why-axial-flux-motors-are-a-bi...
By using motors at each wheel you'd eliminate the need for a differential, saving a good 40-50kg or so. Of course, if you kept the drive shafts and put the motor and reduction box in the middle, you'd be able to use inboard brakes and save a lot of unsprung weight!
It's hard to fit inboard brakes to front wheel drive cars because there's so little space but Citroën managed it with the 2CV and various derivatives, and the GS/GSA/Birotor family. They had an inline engine with a very compact gearbox behind, with the brake discs (drums, on very early 2CVs) right on the side of the gearbox.
You got lower unsprung weight and possibly more usefully the kingpin was aligned with the centre of the tyre, so when you steered the tyre turned "on the spot" rather than rotating through a curve.
Some old Jags and Alfas had inboard discs on the rear axle, which was of course rear wheel drive. They were a bit of a pain to get at.
Wouldn't that make it worse or just ... different. Before this the unsprung weight wouldn't have had a motor in there and now it does. Increasing the unsprung weight doesn't seem a like a good thing.
I think large drones will be another place where a downsized version of this motor will make a huge difference, assuming the power scales nicely with size.
They claim, this compounding effect works out to basically double the effective weight saving from battery and motor.
ie if you start with saving 50kg on motor, and 50kg on battery, you end up saving 200kg over all. Still only about 10% of a typical electric car.
Nitpick: You can have a lighter motor, but you're never going to have a significantly more efficient motor because existing EV motor systems are already 95% efficient or better. The electric motor is an old and refined technology.
And apparently axial flux motors have shorter magnetic flux paths which reduces losses.
ie the efficiency gain is due to the switch from radial to axial flux - not some incremental gain on radial flux.
Having said that the efficiency gains are relatively small - 1-2%.
However again there is a compounding effect, in that the reduction of loss of energy as heat, leads to requiring less cooling - and/or the motor is able to operate a full efficiency over a wider power output range ( as heating the copper increases the electrical resistance ).
https://www.stanfordmagnets.com/advantages-and-disadvantages...
So yeah, weight reduction on EVs is great.
I think people are overlooking that the announcement is for a performance motor meant for the performance market at the moment because that is what the backers of YASA are most interested in because it has the highest margins and prestige. Also not mentioned is the efficiency from the simpler production line.
My impression from what I know is we are looking at an impact equivalent to direct injection engines; not revolutionary, but a major advancement of one component that has significant and consequential effects.
That's why a modern Camry makes almost 200 HP
Suppose we have a motor that weighs half as much, but produces double the output power, but consumes 4x the input power (so, it is half as efficient).
How would that lead to a smaller battery?
Wouldn't we need the component to use less power if we wanted to shrink the battery, rather than just weigh less?
Tesla (I know) claimed a 30kg (?) weight loss on their Cybertruck (I know) just from moving their 12V systems to 48V, allowing for lighter cables at lower currents. Not all such potential is untapped, and my hunch is that there is more to be had with structural battery integration, battery cooling, and high voltage wiring.
For light weight vehicles on the other hand, it might be.
Obviously if you go from eg. a large air-cooled motor to a smaller water-cooled motor, then the smaller motor could potentially dissipate more heat, but that's a different scenario.
The other assumption I probably should have stated is that the two motors are made of similar materials with similar temperature limits. We know the ambient temperature and we know the maximum temperature of the materials used. So for a component made of those materials, existing in that ambient temperature, with an additional heat load proportional to the waste heat in the motor...
The ability to shed heat (assuming similar forced fan cooling, as we were) determines the amount of power we can deliver to the device without increasing its temperature.
The next innovation we need is Aerial refueling[1] for electric planes. High density swappable batteries and high altitude wind/solar plants that can swap batteries mid air. Perhaps some billionaire will develop a large fleet of these to service all flights! If no western billionaires, we just have to wait for China to develop this tech.
On the ground: swapping batteries is faster, and batteries are cheaper than planes or drones. You want the expensive part back in the air as soon as possible so you don't need as many of them. On the whole this probably also simplifies logistics: in civilian aviation airport space is limited, in wartime it's easier to transport one hundred drones and two hundred battery packs to the frontline than to transport two hundred drones
A laser over 10W has safety implications. This is 50,000 lasers all shining on the same plane.
Given your collectors are only going to be say 50% efficient, you're likely going to dumping enough wasted energy into the wings to melt the aircraft - not sure what dumping 3MW of heat energy into a plane would do over an hour, but I suspect it would stat to melt in a few seconds if you're lucky (otherwise your passengers would start getting very toasty)
At 3MW for an hour that's not a great amount of electricity that's needed - at 10c/kWh it's $300 an hour. You don't need fancy things like fusion to generate that. In the UK alone Solar is currently (in November) generating 600 times that - plus domestic installations.
Also planes would not have to wait for a tug to pull back from the gate, which improves turnaround times for the airline.
Not very feasible, but an option that has been thought through.
I guess there’s a system that’s gated to track dependent technologies, to track improvements and what they’ll enable.
Not really. EV's are very heavy from non-motor weight. A Model Y weighs ~4300 lbs. A motor that is 75 lbs lighter is a 1.7% savings. That's not nothing, but I wouldn't say "significant". You can do better by swapping for fancy wheels or eliminating some of the glass roof.
And really this is true up and down the electric vehicle world. Weight-sensitive applications are always going to be completely dominated by battery weight. Making the motor smaller just isn't going to move the needle.
Basically this is good tech without an application, which is why it's having to tell itself with links like this.
But yeah, EVs seem weird except for racing reasons perhaps.
What I can’t figure out is how they dissipate the heat - double digits kw per kg is crazy.
The more of the energy going into moving the vehicle, the less heat the motor has to handle.
And there is no way this is 99% efficient.
So my question still applies. Even 98% is 1kw/kg, or 1kj/sec. or around 3C rise per second assuming the mass is 100% nice clean copper (it isn’t). Everything else will be worse.
Not even counting increasing losses with temperature, it will be a molten puddle pretty quick at that rate without some major active cooling.
Liquid cooling at least for now should work - as long as it stays below the flash point of the liquid I guess.
The YASA axial flux motors benefit from much shorter windings and direct oil cooling which gives an unparalleled performance proposition.
A 200kW peak-power radial motor, run continuously, might typically give 50% of peak power between 80 and 100kW, as a result of thermal limitations. In contrast, a 200kW YASA motor runs continuously at 150kW thanks to the improved high-thermal-contact cooling that oil offers.
Cutting the motor weight probably matters more for smaller vehicles than bigger ones though.
Unfortunately I feel much less safe in a Fiat 500 when a significant portion of cars in the road weigh nearly 3 tonnes and perhaps can't even see me. I suspect most people are in SUVs because they're the pragmatic trade off between safety and convenience, not because they were hoping for excellent performance.
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