I think that at those predicted revs, any saving in weight in this design is going to be lost partially by the addition of heavy sound deadening. I don't need a screaming noise like one of those expensive vacuum cleaners when I am driving. Fix that and all good.

This leap in power to weight just by additive manufacturing sounds... surprising. Additive and other 3D Mfg techniques aren't magic. It's just a faster way to prototype in most situations so I wonder where these gains are achieved?

If only proportional scaling worked, and you could get a 2.5-kilo version attached to each wheel (yeah, plus a gearbox for another kilo or two).

@Thud In some cases, additive manufacturing can let you build structures that would be difficult or impossible with ordinary methods. Any standard machined shape has to be designed so that the cutting head can get to all of the surfaces that need to be shaped. (There are ways around this but they're complex and often expensive.) Additive manufacturing can solve some of those problems. In particular for an electric motor, I'd imagine arbitrarily shaped and positioned cooling channels and possibly wiring channels as well. I wonder if you can cast custom-shaped coils in place efficiently.

Aside from the weight saving, is it more efficient than other electric motors? If it has to spin at 30,000 rpm won't it wear out faster?

@Thud, as a CAD designer, Loz's comment "...combining components into complex shapes that couldn't be achieved with milling or casting..." summarizes the advantages well. When designing for RP manufacturing, one can slim down and beef up components based on FEA feedback to optimize the material to more precisely match the stresses and forces involved. One doesn't have to be concerned as to whether a milling tool can access a recessed or internal region in order to remove unneeded material. In some cases, multiple-material printing can be achieved to further optimize if needed. RP is going to take mechanical design to new levels, and this is an excellent example of that!

Adding to Eddy's misgivings, I'd expect very few loads to match the 30K rpm from the motor. SO, a heavy transmission will be needed. Besides its weight, the transmission will eat up some of the energy. We could appreciate the motor better if the combo were rated against a more typical motor/transmission. Another question: is this a motor/generator? If so, matching it with a gas turbine might be its best use.

i don't understand. Are you guys talking about laser sintering with powdered metal? How do you get a 3d printed part that's strong enough AND mass producable?

Since many modern electric motors are capable of near max output from zero RPMs, wouldn't the 30,000 RPM of this design be more of a capability and less of a requirement to produce it's power? Given it's low weight and high revving capabilities, I could see this being useful in aircraft with electric ducted fan engines. No?

What people rarely understand is that motor size, weight, and cost is highly a function of TORQUE DENSITY not POWER DENSITY.

You can have two motors with the same horsepower rating (power). One operates at 3,000 RPM, and the other operates at 30,000 RPM.

The one that operates at 30,000 RPM has 1/10th the output torque as the 3,000 RPM motor of same horsepower.

There is nothing magical or special about this development. Yes, high speed motors need special design, but the holy grail is moving in the other direction......higher torque for the same power output.

There is a limit to a simple, inexpensive gearbox of about 8-13 to one ratio. Current EV motors do not have enough torque output to directly drive wheels on a car. There is a typical 10:1 gear ratio between EV motors and the vehicle wheels. You want to put a smaller 30,000 rpm motor of same power in that vehicle, you now need a 100:1 gear ratio. You are into specialty planetary and other designs....big, expensive and not as robust with contaminates.

This is before discussing the performance differences. Motor inertia is a significant issue in performance...both acceleration and braking. And motor inertia reflects through that gearbox as the square of the gear ratio. So that 30,000 rpm motor, with a 100:1 gear ratio will reflect its rotating inertia by 100^2 = 10,000 times its actual rotor moment of inertia. Not good.

The holy grail is much high torque with smaller or no gearbox.