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The most I understand about motors is how they typically work and that innovations are possibly more lucrative than battery innovations; this seems like a major

The most I understand about motors is how they typically work and that innovations are possibly more lucrative than battery innovations; this seems like a major innovation. I must be missing something? What's the healthy skepticism here?

emmelaich 7y ago
I don't see anything to be skeptical about; they seem to have done a lot of work and research. One curiosity for me is whether putting the motor in the wheel will work well. It's important to keep sprung weight as low as possible for suspension reasons. Then again, many (most?) electrical vehicles will be run on smooth roads.
- namibj 7y ago
  These motors are light. If you integrate them with the wheel to the point where you mount the tire to it instead of to the rim, you should be close to current mass, possibly breaking even (depending on how much of the axle/differential is unsprung mass, and how heavy the flexible torque transmission ends up being).
  - checker 7y ago
    I already have potholes destroying my rims, I'm not looking forward to the day a pothole wrecks one of my engines!
rossdavidh 7y ago
1) you're right, for every "revolutionary" technology innovation we hear about that actually turns out being important, there are several that don't, but... 2) automobiles were not, until recently, an area that received a lot of effort at major innovation. Credit electric (and hybrid electric) cars with redefining the amount of change that seemed practical to consider.
namibj 7y ago
Emrax sells this technology for years now. This isn't new, and I couldn't find a datasheet to meaningfully compare them with what else is available on the market. I do know of axial flux motors that couldn't have had iron teeth, but I think it was a single-side design with a metal backplate to support the resin-soaked stator windings. I recall a nice discussion about them using GaN power electronics to reach very high efficiencies. Those machines were still hand made last year, however...
- Robotbeat 7y ago
  You can, of course, make an ironless axial flux motor with the resin and wire itself acting as a structural composite. Two-sided. I think commonly were used for solar cars (i.e. for student competitions).
  - namibj 7y ago
    The prototype I touched was for/part of a 200kW pair (I don't recall if each or total) for a demonstrator plane...
kemiller 7y ago
Even if it does what it says, it’s a minor improvement over existing motors once you factor in the rest of the car. The mass of the motor matters but much less than the mass of the batteries.
Robotbeat 7y ago
Radial flux motors also work great. Whether one or the other is better depends on your application. 1) I don't consider this a breakthrough. 2) Magnax's motors are a really sensible design (like Emrax's) and I think they'll do very well. Radial flux motors can achieve just as high of specific power and are already pretty cheap and available. I think it has taken a while for BLDC motors to become cheaply available at high specific powers except for R/C applications, and there wasn't really any fundamental reason why, but it's better late than never. (I make high performance electric motors, including both radial and axial flux ones)
oblio 7y ago
As far as I know electric motors have very high theoretical and also practical efficiencies. Something like 95%+ theoretically, not sure about the practical value, but it's most likely higher than diesel (~40%) or gasoline (less than 40%, probably a bit higher than 35%?). The batteries are the big pain point. A battery that's 50% lighter, has 50% more capacity and costs the same would trigger a technological revolution.

emmelaich 7y ago

I don't see anything to be skeptical about; they seem to have done a lot of work and research. One curiosity for me is whether putting the motor in the wheel will work well. It's important to keep sprung weight as low as possible for suspension reasons. Then again, many (most?) electrical vehicles will be run on smooth roads.

namibj 7y ago
These motors are light. If you integrate them with the wheel to the point where you mount the tire to it instead of to the rim, you should be close to current mass, possibly breaking even (depending on how much of the axle/differential is unsprung mass, and how heavy the flexible torque transmission ends up being).
- checker 7y ago
  I already have potholes destroying my rims, I'm not looking forward to the day a pothole wrecks one of my engines!

rossdavidh 7y ago

1) you're right, for every "revolutionary" technology innovation we hear about that actually turns out being important, there are several that don't, but... 2) automobiles were not, until recently, an area that received a lot of effort at major innovation. Credit electric (and hybrid electric) cars with redefining the amount of change that seemed practical to consider.

namibj 7y ago

Emrax sells this technology for years now. This isn't new, and I couldn't find a datasheet to meaningfully compare them with what else is available on the market. I do know of axial flux motors that couldn't have had iron teeth, but I think it was a single-side design with a metal backplate to support the resin-soaked stator windings. I recall a nice discussion about them using GaN power electronics to reach very high efficiencies. Those machines were still hand made last year, however...

Robotbeat 7y ago
You can, of course, make an ironless axial flux motor with the resin and wire itself acting as a structural composite. Two-sided. I think commonly were used for solar cars (i.e. for student competitions).
- namibj 7y ago
  The prototype I touched was for/part of a 200kW pair (I don't recall if each or total) for a demonstrator plane...

kemiller 7y ago

Even if it does what it says, it’s a minor improvement over existing motors once you factor in the rest of the car. The mass of the motor matters but much less than the mass of the batteries.

Robotbeat 7y ago

Radial flux motors also work great. Whether one or the other is better depends on your application. 1) I don't consider this a breakthrough. 2) Magnax's motors are a really sensible design (like Emrax's) and I think they'll do very well. Radial flux motors can achieve just as high of specific power and are already pretty cheap and available. I think it has taken a while for BLDC motors to become cheaply available at high specific powers except for R/C applications, and there wasn't really any fundamental reason why, but it's better late than never. (I make high performance electric motors, including both radial and axial flux ones)

oblio 7y ago

As far as I know electric motors have very high theoretical and also practical efficiencies. Something like 95%+ theoretically, not sure about the practical value, but it's most likely higher than diesel (~40%) or gasoline (less than 40%, probably a bit higher than 35%?). The batteries are the big pain point. A battery that's 50% lighter, has 50% more capacity and costs the same would trigger a technological revolution.