10 ms·
There are a number of goofy marketing-wank sections on there. Written by an engineer, but it's got the ring of someone really stretching to sound innovative.
by hwillis 7y ago
There are a number of goofy marketing-wank sections on there. Written by an engineer, but it's got the ring of someone really stretching to sound innovative.
> As much as 30% of the typical copper needed is reduced by having all the copper in the coil involved in energy conversion.
That's total bullshit. Here's what they're saying: in a typical motor, at least some of the copper will be outside the iron[1]. There's waste associated with that, since you only need current to be flowing exactly around the iron. However, 30% is an order of magnitude high. The stray field from that copper is almost nil, as it will massively prefer to travel through the iron, so the only real worry is that you've just got extra copper. In modern motors the windings are quite tight to the iron and the stator is long axially.
Even in poorly-wound stubby motors like those in ceiling fans[2] you won't be wasting 30%- maybe 10%. The part of the loop going side-to-side is not wasted, only the parts extending up and down away from the iron.
> The structure of the HET ensures that all of the magnetic field interactions are fully involved in the production of torque.
They must have a gap to get in wiring to the stator, so field can escape there. It also goes straight through the magnets. Any gap develops fringing loss essentially regardless of how big it is, so their reduction in loss is small. And stray field loss is already so tiny it can be neglected.
> The unique design requires no unproductive open spaces. Only the air gap surrounding the coil is left open.
And I wonder how tight their air gap actually is, with all those cantilevered magnets and moving parts. Probably not great. Plus, there's a ton of empty space inside the rotor. They do use the stator iron slightly more efficiently, but in normal motors that space is usually used for bolts anyway.
> Unlike existing conventional machines where torque is only present at an optimum point as it approaches a magnetic pole, the HET has no single optimum point but rather all positions exhibit maximum torque.
> The torque and force will exist while the coil is in the tunnel, regardless of tunnel length.
Well that's just blatantly not true, and also the crossover point between poles is going to be very wiggly indeed. The stator is going to be stretching and compressing itself at different points and the flux has to travel from pole to pole regardless of how many coils are in the way. Their design lets them trade off between torque and speed more easily, but all the rest is nonsense.
> Another advantage is that phases can be software controlled to be grouped into particular patterns. For example, phases A and B can be controlled to act as a single larger pole. Likewise, C, D, E and F. Conversely other groupings are possible with A, B, and C or D, E and F acting as single poles.
Any high-slot motor can be run like this. It's very rarely done because the cost of adding more phases is immensely high. Doubling the number of phases can be multiple times more expensive than doubling the power. And for variable three-phase motor systems the driver is already the most expensive part. If they need all those coils, that's a big problem. TBH though this bit is probably what won them investors- people may be interested in applying their simulation and controls work to conventional motors. It would be deeply challenging to add more slots to the current gold standard motor (PM-reluctance), but it could potentially lead to more high-end efficiency.
> In both of the above cases there is a radical drop in efficiency. The HET Motor addresses this need in a completely different manner. By slightly rotating a single side rotor, an axial magnetic component is introduced. This weakens, as far as the coils are concerned, the total magnetic field experienced by the coils. The degree of field weakening controls the tradeoff between torque and speed.
> For the first time in electric machine history, as the HET Motor enters the Constant Horsepower Region, core losses drop and overall efficiencies actually climb!
Hmm. Yeah, I could believe it. They're also introducing slew, but that's not terrible. It also makes it easier on the driver. However, this would be ungodly expensive.
[1]: https://previews.123rf.com/images/kostiuchenko/kostiuchenko1504/kostiuchenko150400013/39394933-stator-of-the-electric-motor-isolated-on-white-background.jpg https://previews.123rf.com/images/kostiuchenko/kostiuchenko1...
[2]: https://qph.fs.quoracdn.net/main-qimg-245c5636ff7753478e9348d0c7688afb https://qph.fs.quoracdn.net/main-qimg-245c5636ff7753478e9348...
- adammunich 7y agoHello fellow motor nerd!