Home » News & Blogs » Tesla Semi is reasonable, part 1
Bookmark and Share
Selenian Boondocks

Tesla Semi is reasonable, part 1

25 Nov 2017, 05:41 UTC
Tesla Semi is reasonable, part 1
(200 words excerpt, click title or image to see full post)

Tesla finally unveiled their semi truck:
An electric monster with 4 Model S motors, one for each drive wheel, with an astounding 500 mile range (beating most people’s expectations). Fully loaded (i.e. 80,000 lbs total), it can accelerate from 0 to 60mph in 20 seconds. Unburdened, it can do 0-60 in 5s. What’s the point of this kind of performance, other than the ability to go up a 5% grade at 65mph fully loaded? In a traditional vehicle, the conventional wisdom is that an over-powered vehicle will kill your efficiency. And how can you make a 500 mile range electric truck without destroying your payload capacity?
In an electric truck, efficiency and power are related in the opposite way you might expect. The truck shaped a bit like a bullet, with a drag coefficient of 0.36 (like a sports car instead of a “barn”) and an efficiency of better than 2kWh/mile. And the insane performance?
Well, by running more motors in parallel, the effective power loss due to resistance in the coils is reduced since Power loss = I^2*R. Torque is proportional to current and number of motors, so if one motor with resistance R1 needs to generate ...

Latest Vodcast

Latest Podcast

Advertise PTTU

NASA Picture of the Day

Astronomy Picture of the Day