DIY Electric Car Forums banner
1 - 4 of 4 Posts

·
Registered
Joined
·
8,091 Posts
So my question is - do I understand those parameters incorrectly, am I looking at wrong motors/sources, or is Tesla's technology simply that effective and "cutting edge"?
When specs are tossed around, the difference between continuous and peak power is often skipped. If you compare peak Tesla power to continuous power for another brand, you'll see this sort of discrepancy.

Tesla motor technology is not exceptional, although they do use conventional induction motors, while other production EVs use permanent magnet synchronous motors. Model S/X motor technology is so old that they're not even using it for the Model 3, which has PM motors.
 

·
Registered
Joined
·
8,091 Posts
I could argue about the need for massive transmission to handle high power. My understanding is, that mass is needed for handling high torque. With high rpm you kind of get the power for free.
The high motor speed means that the small gear on the motor shaft doesn't handle much torque... but the high reduction ratio means that gear which it drives is large... and handling a lot of torque. That stage is followed by the final drive reduction, with wide gears to handle the forces there. Whatever the motor speed, the end result at axle speed is high torque, so components need to be robust. I'm not surprised that these components are hefty.

An other place was giving the number 350 lbs. for the "electric motor + inverter" and another 175 lbs. on the differential alone...
That would be 175 pounds for the transmission and differential... but the 350 pound weight for the motor and inverter appears to be nonsense. Perhaps it is the weight of the entire drive unit (inverter, motor, reduction gears, differential, case) in the case of the higher-power rear unit?
 

·
Registered
Joined
·
8,091 Posts
One other thing tesla induction motor uses copper rotor which increases efficiency and power output.
Compared to what... an aluminum squirrel cage? Sure, I can believe that copper is better, but it's not exceptional in any way. Both copper and aluminum are routinely used in induction motors.

https://www.youtube.com/watch?v=4OddRX9uO4o

there is also a video that elon explains how this motor can produce such power.
I'll save other readers a couple of minutes: there's no technical information in the sales video, other than that the motor has a copper-bar rotor.

That's one antique video! It actually shows a prototype, from before production introduction (although that doesn't matter in this case because nothing substantial has changed in the Model S since then). The on-screen caption which says "copper rotor inside" is pointing to the wrong place: it points to the inverter, not the motor. I always thought that Tesla made the inverter housing cylindrical to give the illusion of two motors (and of all motor, no electronics), and in this case it appears to have worked. :D
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top