Yasa Beats Own Power Density Record Pushing Electric Motor to 59kw/kg Benchmark
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YASA has achieved a new record for electric motor power density, reaching 59kW/kg, sparking discussion on its potential applications and limitations.
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Not to take away from the exciting achievement, but I always found comments like this kindof unusual. Really, it exceeded even your _most optimistic_ simulations? If the high end of your simulated performance was below what you actually measured, I am worried that your simulation is seriously neglecting something. I used to work in decent depth with three phase bldc motors, so I feel I can say with some authority that these things _can_ be simulated, and while real world data is hard to exactly predict, getting something outside of the predicted range would generally be interpreted as a sign that your simulation isn't so good. But maybe this is just marketing-speak, and their simulations are actually totally fine.
I suspect that the marketing guy's eyes glazed over when the engineers tried to explain confidence intervals to him. He demanded a simple figure. They gave him the median projected value to make him go away. The tested value was above median projection and thus you get this wordspew.
Spoken like a true engineer.
Either that, or your measurements are inaccurate.
If they did simulate this design and it exceeded their expectations so much, either something is wrong with the simulation or some engineer worked some voodoo magic into the very late prototype stages.
The normal scientific reflex is not to hit the marketing guy and say 'we've got a winner, go write it up'.
Also, we don't know by how much the most optimistic predicions were exceeded.
Makes for nice marketing ;)
If I take it literally versus hyperbole and excitement, could there be uncertainty coming from the drive train design choices, system integration details?
Maybe they used a "all our previous tests showed 95% of efficiency compared to simulation, so let's multiply all our results, including top efficiency by this". Then their newest motor had 97% efficiency comparing to previous model.
Short-term peak ratings for electric motors are always huge. You can put in higher voltages up to arc-over. More interesting is sustained output. 1 minute, 10 minutes, 1 hour, continuous duty. That's all about how well it can get rid of heat.
That's why electric motors have a "temperature rise" number on the data plate. That's the steady-state temperature increase from a cold start when run continuously at rated power.
edit: After looking at your account, I see you are John Nagle, and I worry that I am confidently-incorrect here, lol. I'll leave the comment as-is because it is still my genuine belief, but feel free to correct me if I'm totally off!
A big problem with older permanent magnet motors was that too much current could produce a field strong enough to demagnetize the magnets. Supposedly this is is less of an issue in the cobalt-neodymium magnet era, because the coercivity of those alloys is so high.
Then there's finding a pulsed current source to power the windings. Ultracapacitors are good for that.
Then there's finding big enough semiconductors to switch the thing. This, too, has become much easier. It's amazing how much current you can put through modern power MOSFETs.
Then there are mechanical limitations. At some point, something is going to bend from sheer torque. At some point below that, the windings will distort a little on each cycle and wear out.
Applications for this include railguns, catapults, and electrically launched rollercoasters. Interestingly, they're all linear motors.
(I haven't looked at this since the 1990s. The components needed are now far better and more available. Mostly as a spinoff of the electric car industry.)
Cars are a good example of this. There are very few public roads in the world where a car can use 1000hp for more than a few or perhaps a few tests of seconds at a time. On a drag strip a 1000hp street car might run a low 9 second quarter mile reaching around 150mph. That'll put you in jail if a cop sees you doing that speed in a lot pf places. To maintain the fastest speed limit in most countries probably doesn't even require 100hp. So a "short term peak rating" that lets you use 1000hp for 10 seconds will accelerate you in a _very_ "sporting" fashion for as long as you're likely to be able to hold the accelerator down (outside of a race track or autobahn).
Back when I raced quadcopters, I'd happily set them up to pull 200% or more of the rated power of the motors and batteries, because if you kept it pinned at full throttle it would have vanished out of sight within 2 seconds. (You had to be somewhat more circumspect with the motor controllers, the magic smoke could come out of those way faster - sometimes going pop effectively instantly if you started to approach 150% of rated capacity, sometimes even 120% would blow them up ij just a few hundred milliseconds.)
For instance: I know of an invention that will spin up the wheels of a landing aircraft just before touchdown. This saves on the wear of the tires (right now it is mostly the runway that spins them up, as a result of which you see these nice rubber deposits on the touchdown areas). But it would add a few kg to the weight of the wheels so it's a complete non-starter.
Right now, the engine is generally the most expensive as well as the heaviest component in GA aircraft. If you are developing a new airplane, you are often choosing a motor to build the craft around. You would be a fool to choose something that is not tested because (almost) nobody wants to fly a new plane with a new motor. I'm guessing that the cost of one of these axial flux motors is well below $70k. I'll guess $2k... just for ease of numbers.
Our motor is now 46x lighter/hp and 1/35 of the cost. This means we have a lot more flexibility in our aircraft design and our budget for materials/components has gone up, or our market has gotten wider. The biggest hurdle now is to overcome the "unknown engine" which is possible when the exact motor has been mass-produced and mass-used in other sectors. By using this and not painting your design into a corner by relying on the absolute lightest motor you can get, you leave room for future designs in the same space. ie: you have set yourself up to produce the next Cessna 172.
There are additional reasons to want a motor that is 200 hp or less which are written in FARs in the US and copied by other countries. Also, wanting a motor that is more than 200 hp is desirable for other use-cases. By having one motor that can fill both spaces you now have (waves hands) twice the reputation building power.
Of course, there are other technical considerations such as energy storage/weight but the field is so wide that a book could be written on making comparisons. The technical landscape is also actively changing.
[1] https://en.wikipedia.org/wiki/Lycoming_O-360
The global average cost of solar panels is $90/kW. With high tariffs, it's $150/kW in India and $270/kW in the US. Raising tariffs is something like 6 months of price drops. (Meanwhile installed, it costs $500-$3000 on residential properties...)
Solar and storage are some of the most impressive technologies of the past century, and so many people are sleeping on the huge changes it will have.
I don't remember where I read about it first, but the fact that Pakistan is installing gigawatts of solar panels per year made me smile. It's not a coordinated effort, either; people choosing between (1) relying on janky transmission lines, (2) feeding a diesel generator, and (3) buying a rectangle that creates electricity and a cheap battery tend to choose option 3.
The on grid includes panels On grid inverter Wiring Instslation and earthing
A 3kWh system (assuming that's the annual production), is minuscule.
A typical Rotax 912 with accessories goes over 55 kg for 80 HP max and ~ 60 HP cruise. The 100 HP/75 HP version is around 65 kg. The same continuous power with this technology looks like a 5 kg motor and 60 kg of batteries for a direct replacement, if we consider the regular fuel tanks of 50-100 kg on some planes (I used to fly a plane that took 140 liters of fuel with a 100 HP Rotax, but it was modified) then there is enough battery for a flight school needs.
This is a spin-off company from YASA whose purpose is to supply them for aircraft together with other bits.
The world speed record for electric aircraft is held by an aircraft with 3 YASA motors:
https://www.youtube.com/watch?v=4hapBP-Cdis&t=418s&pp=0gcJCd...
Seeing these pop up at a lot of flying schools for basic training.
That teardrop-shaped EV [Ed: Aptera] was going to use the Elaph ones but I think there was some issue with producing enough of them or something like that.
Protean wheels will be on the new Renault 5 Turbo3E which will be a high performance, expensive, short production run.
They make it "easy" to electrify a petrol car and there's a few Sandy Munro videos about the Protean wheels where they test drive a Mercedes converted to and EV with them. Munro was contracted to find ways to get the manufacturing cost down without reducing the durability too much.
You might think that YASA motors would be extra useful for IWM applications where lightness is important but there are other constraints such as durability and fitting in the electronics and it might be essential to have a completely custom design. I don't really know but I do think they should be working together in an ideal world.
They are apparently getting the cost down to where we might start to see them in more affordable vehicles: https://www.proteanelectric.com/protean-showcasing-iwm-techn...
However it does have some limitations as well. For the "general case" it may not be ideal.
Top of the list is protection. The motor is an expensive part, the wheel is an exposed part - bumping a curb for example could get expensive quickly.
Cooling is also an issue. In-wheel motors suggest air cooling, whereas a bigger (single) motor can be liquid cooled.
Currently in wheel motors end up being quite a bit more expensive (because 4 motors not 1).
On paper, in-wheel motors save space, allow for concepts like "4 wheel drive with different lock", save weight and cleaner design (no drive shafts etc), but it's not clear that the end product is better for "every day" users.
Anyhow, I rarely see more than 35 kW indicated for less than a minute at a time.
So can I get my 59kW/kg to go, please? I will take two kilograms.
If the engine is spun to produce electricity, does that make it any different?
These look small enough to use as the wheels. Just like that Audi that Will Smith drove in the film I, Robot.
How well does this scale down? Can I have a 550 watt motor that's 1/1000th the size and that weighs 0.0288 pounds? Would be nifty to have an e-bike without any visible motor.