Disclaimer: I have been hesitating whether to write this article for some months now. I am not an engineer. I am an environmental advocate and avid cleantech follower. I had really hoped an engineer would cover this story, but I have not seen an article that covers this aspect of Tesla’s technology. (I could have missed it.)
The main source for this article is an Autoline video interview done with engineer/auto industry expert Sandy Munro. (CleanTechnica’s Paul Fosse recently gave a great breakdown of a newer Sandy Munro interview. See: “Auto Industry Expert In Lean Design, Sandy Munro, Gushes Over Tesla In New Video.”)
Munro owns a consultancy firm that helps automakers improve their vehicles, their production methods, their understanding of new technology, etc. A link to this video has been provided in multiple CleanTechnica articles. Near the 10:40 mark of the video directly below, Munro begins explaining why Tesla’s motors are “magic!”
After conducting a complete Model 3 teardown, Sandy Munro went from criticizing Tesla’s panel gaps to being absolutely blown away by its technology. He and his team have written a very expensive Model 3 teardown industry report, and he has been traveling the world giving presentations to packed crowds on Tesla’s technology. Unfortunately, his great explanations have not been picked up by the media to the level they deserve.
Last year, his comments about Tesla’s poor panel gaps were covered intensely. However, his subsequent comments about Tesla’s advanced technology have received paltry coverage. After watching numerous interviews of Munro, it is apparent that it takes a lot to impress him, and Tesla does it exactly that. When talking about Tesla’s innovation, he is as happy as a kid in a candy store. Like anyone, Munro wants to make money, but like many engineers, he is intrinsically obsessed with his work and you can tell he really loves this technology.
Tesla’s newer permanent magnet motors are superior to the competition for a number of reasons. This article covers just one of those reasons.
So, why are Tesla motors magical?
A lot of that magic is in the magnets!
Tesla was able to to take advantage of what is referred to as the Halbach array. Tesla’s new permanent magnet motors are an improved design that first appeared in the Model 3. Only recently have the Model S and Model X been upgraded to this new technology.
Magnets within these motors are engineered to create a more optimal magnetic field. Four carefully designed, small magnets that oppose each other are actually glued together to create a stronger — or rather, a more optimized — magnetic field that makes the permanent magnet motor more powerful and more efficient. There are several of these magnets within the motor.
This crucial aspect of the motor is one of the main reasons why Tesla vehicles get more range than competing vehicles that have the same size battery packs.
I am going to try to give a very brief CliffsNotes explanation of the Halbach array. According to Wikipedia, “A Halbach array is a special arrangement of permanent magnets that augments the magnetic field on one side of the array while canceling the field to near zero on the other side.”
To begin with, let’s look at this diagram on the right of this single magnet and its magnetic field. Notice how the magnetic field is symmetrical. It is the same on both sides of the magnet.
The Halbach array is a number of opposing magnets formed (glued) together to make the magnetic force stronger on one side.
The altered magnetic field pictured above is one of the key reasons why Tesla’s motors are lighter and less expensive yet also more powerful and efficient than other motors. In the video above, Munro explains that it is much more complicated than gluing four magnets together. Each magnet is designed in such a manner that Munro does not know how to reverse engineer them yet (the interview was posted to YouTube on January 3rd, 2019, so maybe he and his team are on their way to figuring that out.)
In the Autoline interview, Munro also discussed Tesla’s innovative Superbottle, which also has not been covered nearly enough. The Superbottle is part of Tesla’s brilliant and efficient thermal battery management and HVAC system. If you found this topic of discussion interesting, keep an eye out for a future discussion of Tesla’s Superbottle. It could be called old news, but it is news that has not been widely covered at all.
As a wrap-up, below is a great video demonstrating the Halbach array. Remember, Tesla’s magnets are more complicated than this demonstration. However, the video is an instructive introduction to the Halbach Array.