The Tesla Plaid electric motor has several innovations. Elon says the Plaid’s carbon-wrapped motor is the most advanced motor on the planet outside of a lab. The motor is able to go to over 20000 RPM.
Elon Musk described the carbon sleeve. A carbon sleeve must put copper rotor in compression or it loosens at low temp due to differential thermal expansion. Fiber is wound over rotor at high tension load. A new machine to do this was made by Tesla Automation.
Preload is also helpful for maintaining precise gap to stator.
The main advantage of this is a much stronger EM field compared with a rotor that is held together by metal (usually high-strength steel).
The other advantage is that rotor can go to higher RPM, as carbon sleeve (mostly) stops copper rotor from expanding due to radial acceleration.
Fiber is wound over rotor at high tension load. Machine to do this was made by Tesla Automation.
Carbon sleeve must put copper rotor in compression or it loosens at low temp due to differential thermal expansion.
Preload is also helpful for maintaining precise gap to stator.
— Elon Musk, the 2nd (@elonmusk) June 13, 2021
Main advantage of this is a much stronger EM field compared with a rotor that is held together by metal (usually high strength steel).
Other advantage is that rotor can go to higher RPM, as carbon sleeve (mostly) stops copper rotor from expanding due to radial acceleration.
— Elon Musk, the 2nd (@elonmusk) June 13, 2021
Magnetic strength of Neodymium magnets decreases at 80°C & magnetism can be permanently lost if magnets are left for an extended period of time at a temperature above 80°C
Carbon fiber matrix is generally cured at a temperature between 100 and 130°C
Post-assembly magnetization? pic.twitter.com/yHOVBkxysu
— ALEX 🚀 (@ajtourville) June 13, 2021
SOURCES- Elon Musk
Written by Brian Wang, Nextbigfuture.com (Brian has shares of Tesla)
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
Known for identifying cutting edge technologies, he is currently a Co-Founder of a startup and fundraiser for high potential early-stage companies. He is the Head of Research for Allocations for deep technology investments and an Angel Investor at Space Angels.
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200 mph is both useful to some customers in some locations (Germany, USA once they defund the police, middle east) and is a convenient side effect from the engineering requirements to achieve behaviour that the average customer DOES use.
The rest of this comment is based on my very limited experience with electric motors, and may well be wrong. Read at own risk.
You want good range? You need regenerative braking. That means you want motors that can apply negative 1g or more slowing you down. THAT means you need the motors, and the power cables, and the current controllers, and the batteries, to be able to handle that level of power. Once you've got all that you just reverse the current and it gives you enormous power.
You want good range and long battery life? You need a big battery pack so you are running the batteries at a low C value most of the time, and usually don't drain more than a small fraction of the batteries. This results in a battery pack that can pack a huge wallop once in a while.
You want good range? You make the car very aerodynamically slippery, which gives you a high top speed if you have good power.
Most people won't use high speed, but they DO use, and enjoy, acceleration. Once you've got a motor that gives you high acceleration, that means enough power to reach high speed.
The end result is that by designing a car that has good range and long battery life you almost accidentally end up with something that has great acceleration and high speed.
I was a English police officer starting in 1983 as a Police Constable at Leman Street in the East End of London my shoulder number (British police have a I.D number on their uniform shoulder) was 473HD (HD was just code for Leman st)
1) It's not 70mph everywhere in the world today
2) who is to say it won't be 80 or 90 in the near future? or 200, when autonomous driving makes car travel 10x safer than human driving?
3) there are times when I need to exceed the speed limit and am willing to take the risks in doing so
473 = 1 pint?
Why have a watch thats accurate to 1 second a month etc etc .. the reason is it sells watches (or in this case cars)
Why would having to own your own racetrack make any sense whatsoever? Nearly all racetracks rent their facilities out to track day organizations on a regular basis, and or host such events themselves. Even big facilities, like Daytona International Speedway, are reasonably priced enough that the average person can afford it. Heck, anyone can bring what they've got and ride or drive the Nordschleife circuit at NÜRBURGRING (the larger of 2 circuits there at 21 km [13 miles]), one of the most legendary tracks on the planet, for a mere 25 euros per lap. More moderate facilities are even more affordable. For people that like that sort of thing it's a fairly regular weekend activity.
Why have a car that can go 200 mph when the max speed limit is 70 and you don't own your own racetrack?
This MAHLE motor might be of interest.
https://spectrum.ieee.org/cars-that-think/transportation/advanced-cars/mahles-electric-motor-says-look-ma-no-contacts
https://www.mahle.com/en/news-and-press/press-releases/mahle-develops-highly-efficient-magnet-free-electric-motor–82368
Dual-motor versions of both models have both types of motor. One is better for performance, the other is better for range.
https://arstechnica.com/cars/2019/04/motor-technology-from-model-3-helps-tesla-boost-model-s-range-10/
I wonder why there have been no more switched reluctance motors since the model 3. They have so many advantages. Since there is copper in the rotor of the plaid motor, it's presumably an induction motor, which is inherently less efficient than switched reluctance, and the rotor of which generates heat through Joule heating.
The next step would be conducting nanotubes. Anywhere near copper when cold? Theoretically.