No, as your prior paragraph said, they can use that to gear much, much lower and provide the torque a powerful truck needs without killing the range efficiency.
From a strictly money standpoint. It would be more cost effective to just produce one motor for every model car. Less parts inventory, one assembly line. One trainng line for technicians. It would make every aspect cheaper, faster, better. In economics that a win, win, win for profit. One only wants one platform. Just put the same in every model period and save billions.
Did you see that torque graph? Plaid would give flat line linear power. Unlike ICE which develops power non-linearly. The torque profile would remain consistent over the rpm band.
It's less likely to explode at any speed but that's not why I am writing this. It is in reference to the linked article. This article says that new information has come to light making it clear that the new motors are PMSRM. I tried every way I could to make this consistent with Elon's words
but I can't. They seem to make it clear that the rotors contain copper and there isn't any copper in a PMSRM rotor. So at this point I don't know what to think. Is this guy just another guy on the internet who doesn't know what he is talking about or does he really have some inside information? I guess we'll just have to wait until Sandy Munroe takes one apart to know for sure.
No. Is it linked in this thread?
That is a characteristic of induction motors.
To get torque at low speed requires lots of current and that means lower efficiency at low speeds. That's why BEVs with IM's exhibit poor mileage at low speed.
Show me the torque vs speed graph and I'll lay the power curves over it.
The control algorithms for these cars have to be incredibly sophisticated.
Part of these control algorithms require knowledge of motor rotor position vis a vis the stator magnetic field. Torque is controlled by varying stator current and, in the case of an IM, slip (rotor slip). Acceleration is brought about by increasing rotor slip (magnetic field rotating faster than the rotor). Decceleration is brought about by slowing the magnetic field so that it rotates slower than the rotor. As a consequence of this wheel slip is also known and torque can be controlled to keep it in the linear part of the slip curve. Should slip get out of the linear region it is obviously easily brought back in by reducing motor torque.
I just read the article and it looks like he came to the same conclusions we did in previous threads.
What's interesting is that Elon Musk said of the new Plaid motor "The Plaid carbon-wrapped motor is arguably the most advanced motor on Earth outside of maybe a lab somewhere".I just read the article and it looks like he came to the same conclusions we did in previous threads.
It would be nice to see this new information and who the source was. I'm hoping it was not just from the Alex tweet question below.
In the mean time I have found some video and pictures of the CF wrapped motors as below:
This shows the CF motor assembly from various angles, however not the internal structure of the rotor itself. Note in the presentation animation showing the battery pack, that 3 CF rotors are all shown at once just before the drivetrain assemblies are placed on top. This would indicate that at least on the Plaid (and probably the TM CT at least, if not all models) they are using the same CF motor. It's unlikely they would have done the presentation to not show how it was done. EM also mentions "tightly wound rotor" and "small gap".
On the HVAC he also says it provides 30% improvement in cold weather range, and requires 50% less energy in freezing conditions.
At the 5:17 mark there's a tweet from Alex asking about if they are "post-assembly magnetized", because of the high curing temperatures for CF. Elon doesn't confirm or deny anything here, just says "we have to keep some secrets".
Obviously a IM doesn't have magnets, a PM does, and I think this may be the articles source for it supposedly being a PM. What it actually is a good question, but here is a comment from EM on the M3 motor:
"
It's interesting that he says "partial" permanent magnet rear motor. It's also interesting that they are just testing the units they produce to see which go into a AWD M3 or performance M3. Just like CPU/GPU manufacturing, where die grading allows for overclocking with better heat management. (Just like the post purchase performance upgrade option)
But the reality is EM didn't confirm the CF motor had magnets, in the alex tweet, or if that is how they made it. Plus there are alternative low temperature CF curing methods they could of used instead if the heat demagnetization was an issue.
This question about demagnetization also raises another issue with PM types, in that 80C is not a particularly high operational temperature for a high performance motor.
Has there been any reports of demag in current Teslas reducing range and performance because of temperature?
This is the Plaid CF rotor:
These are the CF rotors and they really do not look like these PM tesla rotors where the magnets are visible on the ends:
These are also interested articles of interest regarding motor design:
https://electrek.co/2018/05/19/tesl...-version-ac-induction-permanent-magnet-motor/
https://electrek.co/2018/02/27/tesla-model-3-motor-designer-permanent-magnet-motor/
BTW this is the Plaid power curve (not torque) from the presentation:
I thought we came to the conclusion that these motors are CRIMs. This article does not conclude that. It states that he knows they are PMSRMs.
Note the date on that tweet. He was clearly talking about the PMSRM motors that Tesla was introducing in that time frame. In those motors part of the torque comes from the PMs, part from reluctance force.
No he didn't. He entirely dodged the question answering it with something about how advanced these motors were.
Eventual demagnetization is a weakness of PM motors for sure and heat accelerates it.
This photo is, perhaps intentionally, too dark to see if the ring has a coppery color and the wrap obscures the bars of the squirrel cage.This is the Plaid CF rotor:
The torque curve is easily derived from this curve as it is the classic curve. [Edit: he said 2000 kg and I heard 2000 lbs so the numbers that used to appear here were off.] The car weighs 2000 kg and accelerates linearly from 0 to 60 in 2 seconds. That's acceleration of 13.3 m/s/s (1.36g!). The thrust required to do this is 2000*13.3 = 26.6 kN.BTW this is the Plaid power curve (not torque) from the presentation:
I completely agree that our conclusion was CRIMs on the other thread. I still think that they are now, even after that EM tweet where he dodges the demag question.
Car weight needs another 1000kg? But maybe you used that in the calc already anyway?
Don't remember the exact words but he said something about other information being brought to his attention without saying where this came from.
I used that mass number because Elon said in the presentation that the car weighed 2000 lbs.
