Tesla Model S Plaid Motor EXTRAVAGANZA!!

Sandy and Ben discuss all the highlights and surprises that the Plaid motor has to offer. Stay tuned at the end for rotor magnet testing.


Plastic-intensive EV Battery Pack Design from SABIC:



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Outro:
Music from YouTube Audio Library [Aka YAL]

#Tesla #Teardown #Plaid

[slartybartfarst]

40 years engineering in big auto ICE, 20 years following EV development. Never thought Id see the day EVs would be allowed to reach their full potential let alone get a deep dive into the engineering. Thanks to Tesla for leading the vanguard and to Munro for letting us in on the detail. Done with skill full genuine enthusiasm transmitted on this brilliant channel, just the best 30 minutes.

[JamesSeedorf]

Rotor is wrapped under high tension, you can't just slide a sleeve over after the fact. You also have no need for multiple directions because 99% of the load is hoop stress from centrifugal forces. Knitting it would actually just make it weaker because the threads would have sharp bends in them.

[oisiaa]

The carbon fiber layer is wound extremely tightly to prevent expansion at 20, 000rpm. Sandy's recommended method would not provide the pre-load compression that is needed to maintain tolerance.

[billw]

always smile when Sandy is happy about the engineering.

[DillonLoomis]

Am I the only one already fired up for the Cybertruck series? Thanks Munro, appreciate all your team does for the community!

[maxtorque]

Rotor magnet skewing is nothing to do with physical torque pulsations that you can feel, because of the high effective rotor inertia and the high gear ratio between the rotor and the wheels, meaning the pulses, should they occur, happen far too rapidly to build into physical oscilationjs / vibrations.

What the skewing actually does is make the backEMF of the machine more sinusoidal, meaning the 5th and 7th harmonic of the fundamental drive frequency is a lower magnitude. If you drive the machine with basic FOC, then the output votlage waveform is sinusiodal, but the backEMF is a modified sine (with the 5th & 7th harmonic components as mentioned) which causes a current ripple. That current ripple not only reduces motor and inverter efficiency, causes a high frequency EMC emissions, cause perturbations in the FOC current control, but also prevent one from running as close as possible to the average power switch current limit (because the peaks would cross the limit when they occur). This is especially an issue with very low inductance machines, ie high power / hgh speeds ones of course.

What Tesla maybe doing is running with an active "feedforward" 5th and 7th harmonic cancelling voltage waveform, rather than relying on the axis current control to simply attempt to follow the backEMF. In effect, the inverter is actually now putting out a non-sinusoidal voltage waveform to match the non-sinusoidal waveform of machine!

Do this, right, and you get higher efficiency, more power, and can run closer to the utlimate limits of the system, and you can run with a significantly stiffer current control loop too.

The downside is your fundamental switching frequency needs to be high enough to be able to accurately synthesize this higher frequency voltage waveform, which requires faster and harder switching of your power elements, and a faster control loop to generate that waveform.

[rickrack]

On the carbon fiber winding, as close to radial as possible is the best. The filament winding industry calls this a “hoop” wind. With wet, or prepreg winding, the flow of the resin allows the individual fibers to nest into the previous layer’s surface. This makes the composite load up in unison as the rotor spins up.
Using a woven “sock” will not match the efficiency of the hoop wound sleeve. As the woven fibers cross each other, the fiber is bent, or kinked, as it crosses every opposite angled fiber.

[-LightningRod-]

placing that converter had such a satisfying and consistent "clunk " when inserted to the various models.

[mr-huggy]

The carbon wrapped stator comes from rockets, let me explain. In rockets we use carbon over pressure vessels to make tanks, these are thin metal tank that are wrapped with thin strip of carbon fibre,
these can take pressures of 5000 psi. With the magnets in the motors trying to push away from each other using carbon fibre wrap makes sense so you can hold in the magnets even tighter. If you use a woven cloth then the seem becomes a weak point of failure which would cause the motor to explode, wrapping is the olny way they could do it.

[freda]

Sandy - This is one of your greatest engineering videos. You and your company are just incredible!

[nilsfrederking]

There was a lot of talking about quality issues in the past - mainly about aesthetic ones - but when you look at the quality of the components and manufacturing methods used Tesla tends much more to the higher end than other EV manufacturers. And of course the "symphony" of arranging the components is of the highest quality :-)

[mukamuka]

Without Munro we wouldn't have this much details explain...!! Kudos man

[legacytesla]

Sandy, the tolerances are too tight to be able to slide over a carbon overwrap knitted. That's why it has to be applied directly to the spool under tension. Especially as the shaft expands and contracts under load and heat.

[mullholand]

I'm so glad that Sandy and co could hangout with Tesla and SpaceX! I think that helps show Sandy how serious Elon is.... no other CEO is in the ballpark....

[dandil]

@16:15 a woven fabric doesn't make sense; the uni directional fibers are keeping it from expanding radially. they only need tension around the circumference, there's no bending forces on the rotor, nor any axial loads.

[farzyness]

THIS IS THE ONE BOYS AND GIRLS. THANK YOU SANDY!

[deanrhodenizer]

I believe that explosive disconnect was a lot more impressive than you may have realized as it happened way too fast to appreciate fully. If you pause the video at 24:39 and then move though it frame by frame, then the explosion was bight and visible in exactly three frames. If you are working with a computer keyboard you can go forward or backward one frame at a time. After you pause a video, pressing the PERIOD key moves the video forward one frame at a time and the COMMA key moves it backward one frame at a time.

[chargehanger]

Pyro fuse on 2 motor phases is to avoid wheel lockup when the inverter fails catastrophically.
On a standard vehicle, it would lockup 2 front, or 2 rear wheels symmetrically, but on the plaid it would lockup a single wheel, and send the car in a violent spin.

[alexforget]

I disagree with Munro about the winding of carbon fibers. They are in the axis that matter, resisting centrifugal forces of the spinning rotor. Other direction would be wasted fibers. Furthermore, by winding the fibers they get pre-loaded and that way the rotor will withstand a lot of force before stretching out, while a jacket put on top will first stretch and then retain the magnet (maybe they could do a preloding by super cooling the rotor before insertion of the jacket ?)

[randolphtorres]

THANKS4GIVING Another Engineering Symphony. KUDOS to the TESLA ENGINEERS and SUPPORTING TEAMS. These achievements are so dam exciting THE FUTURE UNFOLDS.