One problem with electric motors is that because of the speeds at which they rotate, to be useful in most vehicles, they need a gear reduction device. I'd call it a transmission, but usually, these gearboxes only have one speed. This takes the 10,000 rpm from a drive motor and reduces the speed at the wheels while multiplying torque.
What if there were a motor that didn't need to spin as fast as that to make enough usable power and torque to drive a vehicle? If that existed, you could change all kinds of things about electric car design. If you didn't need a gearbox, you would save a good-size chunk of weight and, maybe even more crucially, space.
With that space, you could increase the size of your battery pack, and with the reduced weight, you would improve all kinds of things like handling, range and acceleration.
A company based in Texas called Linear Labs thinks it's figured out how to make that magic motor and if it's right, it could change electric vehicles forever. Roadshow interviewed Brad and Fred Hunstable, the men behind this motor, who claim the Hunstable Electric Turbine (HET) produces twice the torque of a standard permanent magnet motor and three times the power and is more efficient while doing it.
I'm not an electrical engineer, so I won't get into the technical minutiae of how the HET works, but essentially, it uses four rotors rather than the single unit found in many electric motors that acts on the motor's coils to create rotation. The number of coils that the rotors interact with is variable thanks to endplates that can be rotated independently so that they weaken the magnetic fields acting on them, allowing the HET to be infinitely variable for power and torque.
Because the HET generates so much torque at a much lower rpm than a standard permanent magnet motor, it can be constructed out of much more affordable and widely available iron ferrite magnets, rather than expensive neodymium. Neodymium is used in motor applications where maximum torque at high speed is required, but it functions similarly to iron ferrite at lower rpms.
We've already seen significant price fluctuations in rare earth minerals like neodymium, partly because of rare metals' scarcity, but also because most of them are mined in places like China, which for US companies complicates things from a geopolitical standpoint. Being able to use cheap and widely available ferrite could prove to be a huge leg up for Linear Labs.
One thing that the Hunstables are quick to point out is that because the HET isn't built from special unobtanium, and because it uses the same basic principles to function as a more conventional electric motor, it too would be able to benefit from advancements in motor technology. For example, if someone came up with a material that was cheaper and more conductive than copper to use in the coils of a motor, Linear Labs could integrate that technology into its motor as well.
The company has been hard at work making prototypes of its motors for use in various industries. The first transportation application we'll probably see will be in micromobility -- think
and e-bikes -- as early as 2020, followed by
in 2021. It's also possible that we could see HETs employed in larger applications like heavy-duty trucks and even trains later on.
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