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Tesla Model 3 Torn Down, Hacked and Set On a Dynamometer, Exposing Unusual Tech Details (electrek.co)
Rei writes: With an estimated 8,670 Model 3s delivered, a race is on as competitors and owners work to figure out its limits and explore the tech behind it. Many-time Tesla teardown expert "Ingineerix" has posted a series of videos and discussed his findings on Reddit. Among them: what appears to be the industry's first switched reluctance motor, a massive "smuggling compartment" allocated for a future front-wheel motor, no physical fuses (all solid-state), significant wiring harness length reductions via the use of multiple body controllers, a swappable crash energy absorption system, a liquid-cooled compute unit, and redundant controllers for all safety-related systems. He followed up by posting a screenshot of the car tricked into "factory mode" to reveal its internal specs, including a 1200A max discharge current, 370kW max discharge power, and a 76 kWh pack with 72,5kWh usable. Meanwhile, Munro and Associates tore down a Model 3 for an undisclosed, "not Tesla" client, releasing a video criticizing its build quality and for difficulty in accessing the HV cables in the event of an accident (Munroe's claims were dismissed by Ingineerix). Meanwhile, engineers from German automakers were extremely impressed by what they found during their teardown -- particularly the power electronics system, which they described as "compact, expandable, fully integrated, modular, easily accessible, well-protected, reasonably priced and astonishingly clever in many details." Other owners have been putting their cars on dynamometers to measure their power. Drag Times suffered some skid and measured a conflicting 281 / 327.6 hp with 552 lb-ft torque. Contrarily, Tesla Repair Channel found consistent readings around 250hp when starting from 30mph, but consistently around 390 hp when starting from 10mph. The reason for the discrepancy is not yet clear.
I have to say, that between Tesla and SpaceX Musk seems to truly be amazing for at least one thing - hiring engineering talent.
Sure Tesla has some struggle scaling up producing. But a lot of what they have built is really advanced technically, and generally works quite well.
SpaceX is even more amazing in terms of tech, getting stuff working like vertical landings that seemed like it was going to remain as science fiction, while also seeming to be very reliable tech as far as the rocket industry goes which is its own feat (even in modern times you still see rockets exploding on launch).
I'd have to imagine the Boring Company has hired some equally impressive engineers for mechanical engineering and understanding the science of tunneling...
I wonder if the secret is Musk not creating a huge layer of bureaucracy above engineering on top of a decent amount of funding, so they can really accomplish things.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
"The reason for the discrepancy is not yet clear." Uhmmm..... Electric motors display maximum torque at stall
Um... Not always.... In fact, often the maximum torque is defiantly NOT at motor stall for many common electric motor designs. Synchronous induction motors have zero torque at stall and standard induction AC motors often need help to get started by temporally adjusting the current phase of some windings to kick them forward.
DC motors tend to be highest current draw at stall and many have high torque when running slow. For Tesla's drive motors, I'm guessing the stalled torque is pretty high by design but they are not really DC driven, but are really AC motors driven by variable frequency and phases. With these motors you are able to adjust the torque in/out independently of RPM by varying the frequency and phase of the various windings.
I'm going to bet that the discrepancy really has more to do with the motor and drive electronics limits of both voltage and current and the power dissipation of the system. You will lose system efficiency at high currents because I^2 x R losses when the motor is turning slow.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
The "impressive" performance figures are meaningless until Tesla cars can lap the world standard Nurburgring Circuit at speed. Regrettably they can't, because the system shuts down due to overheat.
Management of heating issues is the big arcanum, which electric locomotive designers know fully well. Momentary performance is meaningless, but what are the short-term (3 to 5 min) and hourly and indefinite term performance figures? Heating limits those to such an extent that solderings can melt and the usual flow material must be replaced with "silfos", which is good up to 700 degree Celsius.
You may say top speed lapping a circuit is meaningless in real life, but what about towing a two-axle mobile stable with two horses in it, steep uphill? That also puts the Tesla to test. Not just the motors, but also the battery pack and the power electronics (IGBT and computers) must stay warm, not hot in the long term.
I think european car manufactures are reluctant to commit to electric cars because the "old continent" has a vast body of experience with electric locomotives and they know there are many pitfalls. (The world's thoroughly electrified railway, the Valtellina in north Italy was built from 1899 and started ops in 1902, using locos with 3-phase induction motors.) E.g. France with its immense prowess in HST railway electrification (the famous 320km/h TGV) could order Renault / Citroen / Peugeout to jump head-first into electric cars business, but they don't. I don't think price problems can fully explain that, there must be tech traps they can foresee based on a century of AC railway experience.
Having a private car isn't sustainable. It is a luxury for the 1% in the world. I know, you are going to get really upset by that (but "mah freedom"). Nothing is wrong with having a private car, but to say it is "sustainable" is a joke. Having it cost $75k - $150k is just more of a joke.
Sorry to burst your bad math bubble, but there's over 1 billion cars on the road right now, worldwide. Even if you choose to ignore the fact that many of those are shared by a family of more than one person, you're still looking at ~18% of people that have exclusive access to a car.
Perhaps what you meant to say is that the Bugatti Chiron is a luxury for the 1%?
Game! - Where the stick is mightier than the sword!
Tesla isn't doing that. They are producing $70k-$140k cars for the 1%.
The first ICE cars were also for the 1%. In 1906, Woodrow Wilson declared that gasoline powered automobiles were “a picture of the arrogance of wealth”.
Trickle down may not work in economics, but it has always worked in the automobile industry. What you see in the top-of-the-line cars today, will be mid-range in 5 years, and standard in all cars in 10 years.
The 1% are funding the R&D.