There’s an argument to be had over what type of motor should go in an EV. When Tesla was designing the Roadster and the Model S it had that argument. The firm’s original mavens, before Elon Musk became CEO, decided an AC induction motor was preferable because of the higher performance.In the early cars from Fremont, performance was key. With the Tesla Model 3, however, efficiency appears to have the upper hand.
Back in 2007 EV giant Wally Rippel wrote about the Tesla, Inc. (NASDAQ:TSLA) decision to choose the AC motor. The blog post is relatively long and technical, but the basic conclusion is easy to understand. AC motors have better performance and they likely have a cost advantage.
There are also questions about efficiency. A PM car is intrinsically more efficient because the motor needs less power to run. It also produces less heat, adding to the efficiency.
The choice of original Tesla founders Martin Eberhard and Marc Tarpenning to use the AC induction motors was one of the things that set it apart. Now Elon Musk, who took an interest in the firm in its first funding round, wants to change that direction.
Why did Tesla change its motors?
Why did Tesla change its motors?
We know that the cost of permanent magnet motors has been on the minds of Fremont boffins in recent months. An April interview with Konstantinos Laskaris, head of motor design, undertaken by ChargedEVs.com, may have given the game away early.
When asked about motor cost he said, unprompted, “When we’re talking about permanent-magnet motors, the magnet price in the past has fluctuated so much that maybe this is not very representative of a general discussion about motor cost.”
At the time, as far as anyone could see, the firm didn’t put that kind of motor in anything. Despite that, Laskaris continued, saying that costs of motors were still going lower because of optimization. The entire piece is full of interesting ideas about the future of Tesla motor design. Given that it appears to have pointed to this revelation, there may be more secrets hidden in his answers.
What we can take away from the discussion is informative, however. Tesla has likely made the permanent magnet style motors cheap enough to be worth using. When it comes to the Tesla Model 3, after all, cost and margins are the most important part of the equation.
